I took my car to a certified GM dealer to get it serviced. I had been having problems with the car sputtering and wanting to turn off upon acceleration, especially when driving up hill. The problem was identified by the dealership. Supposedly GM says the problem is very rare. There was a special bulletin issued by GM about this problem.
While trying to pass a vehicle my 4th cylinder misfired and i lost almost any acceleration. diagnostics then found error codes for the multiple misfire and misfire of the 4th cylinder and another error code for failure of the catalytic converter. i replaced all the ignition coils and the catalytic converter to fix the problem
To whom it might concern:
I was experiencing all of thee misfire problems and replace all which might cause the, it was not until check another sight out which offered possible solution I had not considered; Verbatim:
" Number 1 injector harness control wire( black) has a break in it causing all the above issues. You can replace the short harness or find the break in the wire and repair it. I found the break in the harness about two inches back from connector, it makes a hard bend back in to the loom".
I took the advice of the person who delivered the above information and solved my 6 month old problem. I do not know who he is, but I take my hat off to him..
My Check Engine light was continually coming on and I discovered that if I unscrewed the gas cap and then put it back on the warning light would turn off. I went to visit my family in Spring, Texas and I took it to an auto shop for an oil change before I was due to head back home to Montana. The mechanic told me the Check Engine light was on because there were THREE problems with my car...PROBLEM ONE-Serpentine Belt needed replaced (I got that replaced). PROBLEM TWO-Throttle Body Cleaning (I got that done too). And PROBLEM THREE-Needed EGR Replacement. I've had FIVE (5) mechanics tell me they didn't believe the Valve needed replaced. They all say that it sounded to them like it just needed to be cleaned, something about carbon buildup that need cleaned. I had to come home to Montana and my car is in Texas, so I have no idea what to do.
engine misfire caused by coils. I have had the check engine light come on, on several occasions and the DTC code were for coil packs. I have replaced the coils but still have the code. I have determined that the cause is the Ignition Control Module (ICM)