I have a 03 3.1l grand prix. 270,000 miles. It had a misfire on cylinder 1 but i had to keep it running.
It died last thursday on my wife and wouldnt start up again. It was not engine heat related, I checked. I took off the rad cap with my bare hands cause the engine was so cool. Radiator was full, OBD scanner said coolant temp was 200.
We had to push it home (luckily it died in the neighborhood) and still wouldnt start about an hour later.
The engine was turning over but wasnt sounding like it wanted to catch.
The next night (after walking to work and back fml) it started right up with the misfire as if nothing was wrong. Saturday morning I switched coil packs and when I started the car the misfire was gone. Both the Service engine light wasnt flashing nor did the OBD register ANY misfires, but the car was idling rough. Drove smooth but idled up and down between 700-950 rpms.
Today as I was pulling in to a parking lot, temp reading 206, the car died. Coasted to an autozone. I couldnt get it to start again. I popped the hood and took a look and noticed that the number one cylinder's spark plug wire was melted pretty bad. I went in and bought a new wire set and replaced the melted wire. Somehow during changing hoses on the rad system I let it drop and melt against a hot piece of metal.
Ok, still wont start but sounded like itd want to catch sort of. Towed home and right after it rolls off the back of the tow truck it started like nothing was wrong. No misfire and very steady idle.
Decided about an hour later to give it a test drive and see if that was it. Got to the gas station which is about 2 miles away, no problems. Ran smooth etc. Went back out and bam, wouldnt start. Took about 2 hours to get it started and that was by pumping the gas pedal. Drove it home but it died a couple times on the way there. I was pretty much high revving the engine to start it and rolling.
Does anyone have any thought on what this could be? Any tests I could perform to figure out the cause? Thanks in advance!