My 06 was the same, with the ticking too. And it would burn oil like crazy. Ran across a video about clogged up pcv valve. boom! problem fixed! the pcv valve is build into the valve cover. it gets carbon build up and eventually completely shuts. i used a 5/32 bit to clean up the hole and problems solved.
Hey all - so I am keeping up with this thread.... I think I mentioned previously, but I have replaced all of the easy things... throttle body, plugs, coil packs, put a cold air intake system on, replaced both the cam and crankshaft sensors in the front of the motor as well as the VVT and the other one on the sides. I have replaced both O2 sensors (as of today), and even put a new exhaust manifold due to bad exhaust leak, broken bolts, etc. That said... I feel the O2 sensors did a "little" towards improving the idle but probably just in my head. I truly believe it comes down to the valve seals or the valves seating in the head when they close. I have seen a video or two about that on here also. My motor has 188k miles on it but to be honest... runs really smooth when I am moving... just when I come to a stop (red light, etc) it has a really rough idle. When I first crank it up in the mornings, until it warms up, rough idle isn't there, but once that RPM drops after warmed up, the rough idle is back. I have looked into replacing the head, but to be honest, I would almost rather wait until I need to rebuilt or replace the motor as it is roughly a 1/4 of the cost almost just for the head replacement or head job. That is my story and I am sticking to it! :) But I will continue to read along in case someone has an epiphany or breakthrough. Thanks all! Love the Hummer!
Richard, a couple of years ago my 2006 Hummer H3 had a rough idle, it was chugging at idle like it was loading up with gas. There were multiple codes like camshaft position sensor, crankshaft position sensor, misfire etc. I was on vacation at the time when this tragedy struck so I went to the nearest dealership to have them take a look at it. They couldn't diagnose the problem. The lead mechanic told me it was acting like the MAF sensor was bad and to try replacing it. Since I was within a few hundred miles from the house, I went ahead and drove it home. During my investigation I found it was storing all kinds of codes but they were all linked to one timing component. The variable valve timing solenoid. A rather inexpensive part. I had one on hand I had purchased for a Trailblazer a year before by chance and changed it out in about 15 minutes. The problem was solved. There were no more codes and the engine idled smoothly. The problem occurred just after I had the oil changed during the trip (from 10w30 to 20w50). It's my guess that the increased oil pressure somehow popped the diaphragm in the variable valve timing solenoid. I was thinking about doing a video on the problem as it's a real head scratcher if it happens to your Hummer H3, lots of codes for different components but they all go back to the variable valve timing solenoid.
@@KentuckyFriedFixes thank you Chris. I replaced the VVT also abs have been using Mobile 1 Synthetic oil since I have owned it. Motor mounts are good but look like starting to wear so I haven’t replaced them yet. Getting a price from a guy I trust, that does all my “big” work, tomorrow on replacing the head with a remanufactured one.
I had this problem on another vehicle. I figured out that it was the EGR. I replaced it and it ran fine. When cold it ran right. When it warmed up and the egr was supposed to close it ran like it had a cam in it at idle. Once the egr was replaced, it ran smoother than the day I bought it.
I have the same issue and have replaced all the above with new OEM parts and full synthetic fluids in everything, Still idles rough. Its either the torque Converter or the head, Seals in the head are prone to failure. Other than that it runs great.
@@KenHMladin yes, most likely the head. I had my torque converter replaced when I did the transmission a few months ago. Going to have cylinder pressure check done.
Motor mounts are why you’re getting all that movement… and the clicking is your exhaust leak at the manifold… if you replace the gasket and seal at the manifold that clicking will go away
Watching mine is doing the same thing. Replaced the valve gasket, hose, coils and plugs today we found it had an oil leak as well. All that I am hoping corrects it.
im chiming in late here but ive been having issues lately with my 06. seems simple, but check that the vacuum hose on the underside of the intake at the rear. if that hose is not connected you will get a very rough idle. i recently changed vvt and o2 sensors, plugs and coil packs. but now i have a crack in the exhaust manifold. if it aint one thing, its two!! see you on the road my Bros!..
Check the wiring under the black plastic valve cover. There are the wires from the coil plugs that run to the timing sensor the sit right on top of the valve cover and are routed through channels in the head cover to the control valve. Those wires can become exposed from rubbing on the channels and ground out. Hope it helps.
I'm pretty sure it's the accelerator pedal position sensor. I had the same issue. Replaced mine, initially let the engine run without touching the pedal for a good 5-7 min then shut off the engine. After putting 100 miles on the truck it has definitely improved the rough idle. I think it takes a while to relearn the intake parameters in the ECU. Hope this helps. You can't just put a new pedal in and think it will fix it immediately. It takes a while for the ECU to relearn its new parameters.
Have you changed anything or cleaned anything. I kinda get the same problem. Basically once the car warms up about 550 RPM and do like a rough aisle little shake. What I found in my own findings is maybe oil pressure. Mine's dust consume a lot of oil. One thing I found online was someone changing the map sensor and harness/wiring and that's all the issue.
I've replaced MAP, MAF, drive belt, throttle body, tensioner, plugs, coils, fan clutch, and today I'll be replacing injectors and harmonic balancer. I've cleaned both camshaft position sensors and VVT solenoid. Mine doesn't consume any oil, or leak any oil. Oil pressure seems fine. 550 at idle seems low though. Mine idles at about 750, which seems to be about right given the information that I've seen.
@@IamFreeRu so it seems to be oil residue in the baffles of the valve cover that causes clogs and eventually these clogs makes the pressure get high enough that the oil is forced through the breather hose. Some say to replace the valve cover, but I took mine to a shop that used an engine cleaner (it was like $75-85) and it solved my issue. I would recommend that you have them clean the throttle body at the same time. Those two things made a huge difference for me!
As crazy as it sounds check your water pump. I had same problem with vibration. My serpentine belt needed change so when i took it off i checked water pump for play to see if bad bearings. I grabbed the front and went to spin fan mount on pump. I could barley turn the pump, it was almost frozen. It did not leak or anything. I changed pump out and idel was back to normal. Maybe not your issue maybe its a one in million but what my problem was. At idel the bad pump was bogging engine down. Easy for you to check, loosen or take off belt and see if you can spin pump by hand... Oh my tensioner was bouncing make noise to. Thos solve that problem to. I image if i let it go eventually it would have froze solid and belt be squeling and rig over heat..never had a water pump start freezing up. My gas mileage and power went up to...dont know if this is common but check it..
That doesn't sound crazy at all. In fact, I already had that idea. So I removed my belt and started the engine belt-less, and the vibration was still there, thus removing all the accessories from the equation. Good thought though.
Hey Lenon check those intake manifold bolts to make sure they're tight. Sometimes if you get a used Hummer H3 you'll find somebody has been there before you to replace a starter or alternator, removed the intake manifold and didn't get everything back tight when they finished. Also you should check the MAF sensor to make sure there isn't a small piece of a leaf or other debris on the sensor itself. Just pull the sensor and perform a visual of the area on the sensor where the little wire is, that's all that's needed you don't wanna touch that part of the MAF sensor.
Already replaced the MAF sensor. I've been putting off checking the intake manifold bolts because they're such a pain in the ass to get to. When I do though, I'm going to replace the injectors while I'm there.
@@lenonkitchens7727 A little twisting and turning and you can get a socket in there with a long extension. Mine were loose when I first got my H3. Unless your Hummer is throwing a code the rough idle will be difficult to track down. Mine had a rough idle at one point without a code and it ended up being a piece of leaf laying across the MAF sensor wire (inside the breather duct) I didn't find it until I was replacing it with a new MAF. Went ahead and installed the new MAF anyway and a year later the new one went bad. Now it has to original back in place still working fine. Some guys say the breather hose from the air cleaner to the valve cover will cause a rough idle but mine is old and cracked and it still idles smooth? (Hose on order anyway 😉) Good luck!
@@KentuckyFriedFixes Man, I can't even see the bolts. Maybe just try for it by feel? It's not throwing any codes. I'm really thinking O2 sensors right now. I have some on order, and we're going to see where it goes after that. Thanks for the input though, much appreciated.
@@KentuckyFriedFixes Here is a good video on the intake manifold bolts - location and tighten pattern. I will take a look at mine this weekend just because. I also replaced the MAF sensor when I did the cold air intake.
Hey Lenon, I Just Got A 2006 Hummer H3 Was Having A Similar Problem Vibrating When Idle. What I Did Was Look Around. What I found was the Oil Pressure Sensor Not Connected. The Little Pin Inside The Sensor Was Bent I Just Unbent It Cleaned It With Alcohol And Connected It. Turn The Key To On Like 2 Minutes But Didn't Turn On The Hummer To Let The Computer Recognize That It Was Connected Again And Problem Resolved. Little Things Make A Difference 😂
Nevermind, I misremembered. It wasn't leaking, I had an oil pressure warning on the dash, but the oil pressure was fine. Replaced the sending unit, and it went away.
My 06 H3 was rough after changing coil packs. Then check engine light came on. The code P2122 & P2128 said throttle pedal sensor. After replacing it smoothed out.
I suspect it was the throttle position sensor causing it to idle too low. I can't confirm though because I no longer own it, unfortunately. I got a deal on it that was too good to pass up, though I've regretted it several times since. I miss my hummer....
you wont get a smooth running h3. the inline atlas engine just runs rough from what ive learned with my 06 h3. my motor blew and put another and same rough idle. 5 cylinders just wont even out and run smooth. they are also notorious for having temp gauges that always run above the half way mark even though the temp is good.
By cleaning the throttle body helps a lot check your plug gap and that seems to help a lot too and run some Lucas in your in your gas about every fifth tank and that'll take the smoothness and but keep your your stock air box in there and get rid of that resonator out of the center put it put a spacer in there with a with a line going to your your PVC and take the the block off of the back side of the air box going into the fender well so it can get more air so you should be good to go I have an '06 and it runs great it's got 126,000 on it and runs good oh put a 3-core radiator in it with a with severe fan clutch for keeping the temperature down for the air conditioner Good luck from Oregon
My 2006 130,000 miles Hummer H3 3.5 liter 5 speed manual tranny doesn't drop its rpm's between shifts...and sometimes it actually idles up to 2500 to 3000 rpms if I am shifting between 3rd. and 4th... or 4th. and 5th gear. I have only owned this vehicle for a short time so I don't know if this is an old or new issue. I have cleaned the Throttle Body, the vent tube and installed new plugs (I recently changed the Nylon Shift fork in my Transfer case too... pain in the ass job that was !) ... not sure where to try next. Any suggestions ? UPDATE: This idle problem has fixed itself !
I'm assuming you're actually taking your foot off the gas pedal when you shift. ;) I would try replacing the accelerator pedal position sensor. It's attached to the top of the pedal, if I remember correctly. And yeah, dropping that transfer case without a lift was no freaking joke. Once that's done, it's cake, but dropping it and getting back in....hoo boy!
@@lenonkitchens7727 I'm a 75 year old retired Over the Road trucker... I have over 2 million miles under my belt. I know how to shift a manual Trans ! lol Yeah, my 25 year old son had to drop the Transfer case for me and put it back up and in when I finished the internal work on it... before I did the Transfer Case fix my H3 wouldn't even roll on a slight downgrade... now it rolls great... gotta help my crappy (13) mpg a lot ...plus, there has to be a ton less stress, wear and tare on everything involved. I'm thrilled with that improvement ! Thanks for your fast reply and suggestion ! LiKED/SUBSCRIBED !
@@Snailmailtrucker Yeah, I was just joking about taking your foot off the gas. :) My 24 year old son had to help me with the transfer case as well. You're welcome, and I hope replacing that part actually helps you. I think you have to replace the entire pedal, but I'm not certain. Let me know if you have any trouble finding the part.
I came to the conclusion that it was just idling too low. I haven't fixed it though. At some point I should take it to a dealership and see if they can program it for a higher idle. Or it could still be a bad sensor somewhere. I gave up though. I loaded the parts cannon, and I missed. I got a new vehicle, so the Hummer is sort of on the back burner for now.
Engine mounts are fine. The only problem is at idle. No issues shifting or revving. Since I made this video, my idle has dropped to about 550 from 650-700, and it's gotten worse. It's probably O2 sensors or something.
I had the exact problem on my 06 and it was the head, my mechanic swopped it out with a refurbished one and it runs great with no vibration other than normal.
@@lenonkitchens7727 I have heard could need a valve job, so I may pursue that after the O2 sensors, just to at least get it running as best it can as it is fun to drive.
I found a post on some obscure H3 forums that claimed GM was doing ECU updates to fix this problem when the vehicles were new. I don't know how much I believe that. But no, I've been able to mitigate it some, but not fixed as of yet.
@@MakingCampB No, I gave up. I can't find anybody with the equipment to do it, and I'm not going to take it to a dealership, so I'm sort of stuck as far as pursuing that.
It could be your gas pedal since it contains the throttle position sensor, you can buy one and install it in 5 minutes and just return it if it doesn't fix the issue. The new pedal throws off the ECU for the first time and resets all the sensors after running for a few minutes. You can also have someone rev the engine to check how bad the engine moves to see if the motor mounts are worn. I guess the most obscure issue could be a problem with a clogged exhaust, if the gas can't escape easily it could give you a rough idle at low rpms that goes away when there's more pressure.
You know, I thought it could be the throttle body position sensor, so I replaced the throttle body. I wasn't aware it was in the pedal. Maybe I'll give that a try. It's not a motor mount, movement on revving and changing between reverse and drive is minimal. THanks for the suggestions.
@@cflip7452 It's all part of the system and my pedal was causing a rough idle. At first I'd get the reduced power error while driving that only happened if I floored the gas pedal but then the same error came up when starting the truck. The check engine code was a TPS error and after looking up the issue, I narrowed it down to the gas pedal that includes a throttle position sensor for the drive by wire system. The pedal swap stopped the TPS issue and rough idle. You can buy the pedal in person for $80 and swap it out faster than it takes to fill the tank with gas and go back in to return it if nothing changes. It's just one connector and 3 10mm bolts so as far as troubleshooting goes it's probably the fastest and cleanest test.
Still have the rough idle. Next going to put a new ac Delco crankshaft position sensor, finger crossed. I just wish I could raise the idle 50 to 100 RPM and that would fix it. Does anyone know how to raise the RPM...even with a hack or mod?
Nothing every worked for me. About 2 months ago I got a deal I couldn't refuse on a 2022 Frontier, so I had to trade the hummer. I never did the crankshaft sensor, but I don't think that would cause it. Let me know if it works though!
I have the same issue with my 2006 H3 - 188k miles - changed plugs, coil packs, new throttle body, cold-air intake, changed VVT (two of them... I think one is called something else) and I changed the Cam and Crankshaft sensors. Changed Exhaust manifold and cat due to a bad exhaust leak. I am going to order the two O2 sensors and give that a try. Like everyone else, pulls and runs fine, but angry vibration at idle. Just annoying mostly.
friend, this is normal in hummer h3 3.7? walking he's great, but standing still he does that. Any suggestions of what it could be? look please. TKS ru-vid.comCbdppORFOUA
@@lenonkitchens7727 mine does the same thing snd it has 159,000 miles and have tried everything:). Still runs great and pulls fine just that dang idle. Thinking about trying some O2 sensors
If you ever figure it out let me know. Trying O2’s tomorrow just because of mileage but all and all I’ve owned it for 5 years and it’s and 2007. Think it’s just the nature of this motor. Still reliable though👍
@@cflip7452 Mine has 230k on it. If the O2 sensors help, let me know. I've considered changing them, but thought it highly unlikely (without a check engine light) so I haven't bothered. I've got a new set of injectors I need to get on it to see if that helps, but getting to the fuel rail on the damn thing is a massive pain, and I haven't gotten around to it.
Yeah I’ll let you know there suppose to be here tomorrow. Thought I’d try them after 5 years lol. I pretty much just assumed it’s the nature of the I5 and honestly no check engine lights and runs and pulls strong. Doesn’t idle like a Cadillac but maybe that’s the worse of it:). Everything is great though and should be good for 300,000 plus on motor from what I hear. I’ll let you know what O2’s do. About $100 for both and thought I’d give it a go with the mileage
