Hello,
My 1999 Bonneville started acting up recently. Was curious to see if the problem may be common to this year to help me troubleshooting. Car starts and runs fine. Drive for a bit and when you go to stop it wants to stall. Seems maybe the converter lock up is not releasing properly. Or some other issue. Today the check engine light came on. After I parked the car for a few ours I went out and started it and the check engine light was out and car acted fine. Any clues before I tear into this rascal. Thanks in advance. Mike.

Have it scanned for codes. Even if the CEL went out it should still be stored. It could be a number of things. Dirty MAF, sticky IAC, vac. leak.

egr is the usual suspect when you are talking about running poorly on decel, but like mentioned need to scan it before shooting in the dark

Definately scan. Kinda sounds like it'* having trouble holding idle.

Borrowed a scanner from a friend. Will check it tomorrow.

Scanned today. Got a P0102 MAF or VAF A for low input. Cleared them and drove the car and rechecked and it didn't recur. Could this be an electrical issue?

https://www.gmforum.com/showthread.p...ighlight=p0102

you can get maf cleaner in a spray can i would try checking the wiring and cleaning first and see if the code comes back then maybe you might need to replace it.

Cleaned the MAP,replaced the air filter, cleaned the diffused and all the connections. Car still stalling on occasion, but the check engine light doesn't come on so the OBD isn't showing any codes. I'm wondering if I may have got some bad gas, (water) because this issue began shortly after a fill up. Dumped a bottle of dry gas and will drive for a few days and see what happens.

check the fuel pressure regulator for a diaphragm leak. Pull the vacuum hose check for fuel or fuel smell. Bad FPR can cause stalling at stops. Also long crank time when engine is warm but starts fine after sitting overnight