2007 Hummer H3: misfire or rough idle

Filed Jan 16, 2021 · Engine · 95,000 miles · CA

Vehicle misfires frequently. Engine will nearly stall at idle due to misfires and shake the whole vehicle. Lack of power and efficiency. And juddering while accelerating. It is known to gm and many people have had to resort to cylinder head replacements costing hundreds at a minimum.

Filed Jun 20, 2018 · Acceleration, Driver assistance · 180,000 miles · FL

Vehicle instrument panel warning shows: service traction control reduced power stability system failed vehicle misfires when this happens sometimes vehicle shuts off in the middle of the road when trying to restart it does not restart sometimes after this

Filed May 4, 2016 · Engine, Transmission · 103,306 miles · MI

The vehicle just lost power and almost lost ignition while driving 50 miles an hour. Diagnostic code state, misfire in cylinder one. Valve springs ( rocker arm) are breaking prematurely causing a leaking valve problem. Mechanic also noticed other springs were fatiqued causing a looser than normal seating. Gm service manager mention a spring problem on 2006 2007 rendevous. One of the largest complaints with the hummer 3 is this leaky valve syndrom which the dealers know about. Some occuring with the vehicle having only 30,000 plus miles.

Filed Apr 6, 2016 · Driver assistance, Engine · 110,488 miles · IL

Bought 2007 hummer h3 at the end of february as is in chicago at net motor cars addison illinois for 14000 and drove it home 150 miles away and was told by dealer to take it in to gm dealer and have my ABS system flashed by them and all warning lights will go away gm poages had my car for two weeks cost 560 dollars to repair then a day later check engine light came on took it to a shop and they said if gm had it checking for codes they should have seen the wire if they had it on machine looking for codes because that wire had to be in place to read the codes so he told me to take it back to them to repair it for free. I told him no for him to go ahead and fix it for a hundred because if I take it back to gm poage what other trick do they have up there sleve if they fix it. So he did and it showed multiple misfires and a steady misfire on cylinder 5 told them to fix it costing 1929.90 car has been in two different shops two weeks at the gm dealer poage auto mall in decatur illinois very disappointed on there behavior of being shady if they had it hooked up for two weeks on a code reader why didn't they see misfires. Will never do business with them ever they lost a 2000 dollar job and my future services like changing oil ect. This is bad business. Getting my car this week from south shores audo which will have my business in the future. Gm or at least decatur poages auto mall should be investigated by trying to screw over a woman and who else they can they pulled wire so I would bring back to get radio replaced as I was because I only had so much money to replace I think when I was going to bring back in for a refurbished trade in radio they were going to install it then hook wire back up and surprise me with the misfires and a probably 3000 dollar job. Also south shores auto told me nothing wrong with radio

Filed Apr 27, 2015 · Brakes, Engine · 100,000 miles · KY

While driving at 65 miles per hour the vehicle dash lit up all service lights the vehicle went into reduced power mode not allowing the vehicle to exceed 40 MPH and ABS sensors came on staying traction fail, ABS fail, began to stutter and stall. Took to shop. Vehicle running codes for spark plugs, replaced spark plugs. Few weeks later did it again, this time saying throttle body. Replaced it, a month later did it again, each time in major traffic having to pull off roadway to avoid an accident. This time says misfiring, throttle body, ABS,TPMS, thermostat, etc. Take it to have compression test run and system says cylinder failure. Do research on issue and find that there are hundreds of complaints about this online having caused accidents and thousand of dollars spent by consumers after having accidents but no known fatality so gm will no recall or honor the issue repairs. Almost all of them happening at 100k miles.

Filed Feb 26, 2015 · Electrical, Engine · 66,790 miles · CA

Engine check light came on for very short period of time then went out. About a week later it came on again. Went to chevy dealer who ran a quick code check which indicated the number 5 cylinder was misfiring. The chevy dealer indicated the engine/power train warrranty had expired and the problem could be from injectors, plugs, coil and valves. Initial computer check would cost $135. Vehicle is sitting in my garage awaiting money to get it checked.

Filed Apr 20, 2014 · Engine, Transmission · 44,000 miles · TX

44,000 miles check engine light came on . Took to dealer I had a cylinder 5 misfire code p300 couple thousand miles later my truck was still showing multiple misfires. I had to replace the radiator because it was leaking and thermostat at 46,000, april 2011 at 65,000miles my transmission went out completely and had to be replaced july 2012 air stop working took to dealer they said I had to replace the fan blower motor resistor. Researched and founded this was a known problem for hummers the motor gets to hot and melt causing the fan blower to go out . Several months later check engine light came on several more times took to the dealer said they couldn't find problem and cleared code my check engine light came on again so I took to auto zone diagnostic showed cylinder 5 coil multiple misfire so I had spark plugs changed alone with all five ignition coils. Couple months later check engine light came on again took it to dealer diagnostic test reveal code po 300 again and couple other codes dealer said my truck had an emission leak. Multiple misfire ,cylinder 5 and a small crack in the head. I didn't understand how that magically happen. I paid the dealer to fix this on march 2014. A week later check engine light came on again . Took to dealer diagnostic showed emission leak apparently they didn't fix it the first time. Week later check engine light came on again took to dealer and diagnostic test reveal torque converter clutch solenoid .dealer said I need transmission replaced. I'm confused at this point the dealer put a newtransmission 3 years prior .my truck has never been over the road. I only drive locally. Now at 103,000 miles the dealer is saying I need another transmission . Something is not right here. After researching I've found thousand of hummer owners experiencing the same problems I've experienced. Something needs to be done to protect consumers.

Filed Apr 8, 2014 · Acceleration, Engine · 66,000 miles · WI

I own a 2007 hummer h3 with 66000 miles on it. It has been diagnosed as having a bad head due to the use of soft metals for the cylinder sleeve. Due to this, there is sudden reduced power. The cost of this fix is about $4500.00. My truck began with a check engine light on (autozone) said it was a misfire on cylinder #5. I went to the local dealer and asked them to look at the truck. They diagnosed it as a #5 cylinder having the compression leak of 90%. In looking on the internet (at hummer forums), I observed that quite a few hummer h3 owners were writing in about their experience with misfires and bad heads, at about the same mileage. I think this needs to be looked into and that gm should be ordered to do a recall. This is the same problem they had with the 3.5l engines they used in their pre-2007 hummer h3 and colorado. I am going to write my congress rep and ask that with the problems that gm is having right now, that this also be moved forward and that they order an investigation. Any other hummer h3 owners with the same problems should do the same thing.