So the other day I took my 08QP Sport GT (91K miles) off the tender after a month I was away and did an oil change.
I then just turned it on and left it running while I went inside to wash up. When i came back out the engine was misfiring like CRAZY!!
I turned it off right away and hooked up a scanner. The only codes I got were for random misfires on literally every cylinder. Spark plugs were done couple months ago and coils are fine, so I ruled that out.
I happen to have another MAF and replaced it with the same results.
So after messing with everything and trying to figure out what is causing this I found a pattern.
Every time the engine hit operating temp, the misfire would begin and not go away.
One thing I did notice was then I turn the key to ACC, I didn't hear a buzz like I usually do (I believe that's the fuel pump sound).. But there is no problem with it since its starts right up and runs fine...
until it hits 195 deg.
I'm lost... the only thing I didn't do yet was look for vacuum leaks. I ordered one of those EVAP smoke machines off ebay to check for leaks, so that one more thing I need to do.
But If I had a leak I would assume I'd get some sort of code besides just misfires. I disconnected the battery over night and did the proper relearn process, with no change.
I'm stuck and Its so weird. Its smooth as any other day just until it hits 195 degrees.
It only happens when I'm stopped... if I'm driving there are no lights, no misfires, and the car runs just as powerful as it always has... but when i come to a complete stop its starts acting up.
In the last year I changed plugs, oil change, flushed radiator, and replaced the coolant temp sensors along with he thermostat.
Brand new up stream O2 sensors just cause I found them cheap.
I have FD DBW, Larini mufflers and x-pipe, 91K miles. I'm totally lost, please help