I have a 1997 Bonneville SE that begins to stall whenever I come to a stop, let off the gas, shifting into drive, and in low RPM situations (slow crawl traffic).

I've had checked/replaced: IAC Sensor, MAF Sensor, Fuel Filter, Fuel Pump, Vacuum Lines, Battery Terminals, and it still hasn't corrected the problem.

It starts like a champ, then the idle rpms vary wildly then it likes to stall. I basically have to start it and immediately go.

My mechanic is stumped, and nothing has worked so far- anyone have any ideas?

sounds like vacuum, but leaks are hard to find. spray some carb cleaner and listen to the engine for differences. common thing to look at is the boot on the tb, the line that goes to the fpr and evap purge. if they are cracked at all just replace them

I've had the cracked boot replaced and all the wires/lines replaced too. Still with the problem. Could it be the TPS or the FPR?

Also, did the carb cleaner test, soapy water test, and a smoke test, and I don't have any leaks.

take the line off the fpr and smell it if you smell gas its bad.

https://www.gmforum.com/trouble-shoo...sensor-279319/

Checking both of those right now! Thanks!

Which things have you replaced? MAF? IAC?
Disconnected MAF to test?

Have you checked fuel pressure with a gauge?

Have you R/R the EGR? Given it a mild wack to see if it'* staying open bleeding in air?

Checked the PCV for proper operation and o-rings?

My thinking would be to check the temperature sensor for the computer. Your mechanic should have checked that with a scan unit to see that the computer was getting a reading to use for mixture that was close to the actual coolant temperature.


Have you sprayed carb cleaner over the intake manifold to see if air is being sucked in through a crack?