97 sunfire, stumbles at idle, then dies

02-25-2011, 05:29 AM
97 sunfire 2.2L auto trans

had some timing chain slap, so i replaced the chain, gears, and oil pump.

the car usually runs pretty well now until it warms up. then it will stumble at idle (like at a traffic light). when i start going it will stumble like it is misfiring and usually stall. engine will try to rev with throttle, but it won't accelerate. replaced plugs and wires and still having the problem. sometimes i can get stopped and in park while it is stumbling, and it sounds like a miss in cyl 1. i was thinking coil pack, but shouldn't i be hearing a miss on #4 as well or getting a CEL? when it dies, it will usually start up and drive, but the stumbling will start back up as soon as i slow down or come to a stop. also, but probably unrelated, the ETS off light is on. No CEL or engine codes showing. any ideas would be appreciated.

Blue Bowtie
02-27-2011, 01:13 AM
The most obvious question is whether the timing chain was installed correctly. That's not at all a question of your abilities, but whether the marks were aligned and the marks aligned with the old sprockets. I've installed V-8 3-way timing sets (4) that were marked incorrectly right out of the box, meaning the tooth stamped at TDC was way off the intended (matching) broached keyway for that timing range. Given the quality of goods produced any more, it's always a valid question. Some things just don't translate from French-Canadian to Lower East Pakistani very well.

Also, fuel pressure and flow can have an effect similar to what you are describing.

A #1 coil pack failure would probably show up on #4 as well, but since it is a wasted spark system (plugs in series) a shorted #1 plug may have no effect on #4.

02-27-2011, 04:37 AM
it was the fuel pump. replaced today. drove 200+ miles with no probs.
in general, after about 45 minutes, the old pump would start to crap out. the first time i checked fuel pressure (before my first post) it had only been running about 30 minutes.

i feel ya on the gear marks. i made sure the line-up marks matched the old ones before installing. heard that story too many times.... :-)

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