92 Bonne intermittently loosing power

HI all.. I have a 92 bonnevill (non supercharged) with about 220K on it and it works great about 90% of the time.

intermittently, the engine will loose power and sputter after it has warmed up for say 20 minutes. if you keep you foot down it will stall out, if you let go, it'll recover and idel like there's no problems at all. when it's acting like this, you are lucky to get the car above 30 MPH. shut off the engine for 1/2 hr to an hour and the car will run just fine for another 20 minutes to a week.

There are no engine codes, the plugs & wires are fairly new, the fuel filter has been replace, crank sensor is replaced, the Mass airflow sensor's replaced.

one thing i did find strange, is i cannot get the computer to come up to engine on diagnostics to check closed vs open circut the check engine light still keeps flashing 12 (engine off diagnostics/no rpms/etc)

i'm only assuming i tried getting to the engine on diags correctly, the instructions are pretty simple to do, (start engine, insert scanner)


any help would be appreciated, it's very frusterating to replace a part and you'll think it's fixed after a week of long driving, only to have it fail again.

tnx

Hmmm. That's interesting... My first thought is fuel starvation. Say for instance you have very little fuel in the tank. The car can generally idle but when you give it gas, it will try to stall. Have you checked or replaced the fuel filter lately? For under $10, you just might want to chamnge it anyway.

The fuel filter doesn't really explain why it runs fine after an hour though. Perhaps all the crud in there settles and fuel flows correctly?

Since you've already tried a filter, and you're not getting any trouble codes... that leads me to think its a starvation problem. Have you ever checked the fuel pump... the system has to maintain a certain amount fuel pressure (like 14lbs or something)... after 220K I'd think the stock pump might be alittle week. You can get a gauge to check pressure without disconnecting anything.

That's about all I can come up with, seeing the parts you've replaced already.

Good Luck.

:disappoin Uh... reading is fundamental...

I missed this part

the fuel filter has been replace,

I would agree it is the fuel pump, my camaro did the same exact thing, sure enough it was the pump, same thing symptoms, would stall, quit, then wouldn't start for half an hout or more sometimes.

It's fixed! Fule pump was the problem.. It's been running for 2 weeks /w slightly more power than it has had in like 6 months..

Thanks.