PontiacBonnevilleClub.com

I have a 03 bonne sle with 122k. Just yesterday she started to die out but would come back to life. She would dip to about 500rpm then shoot back up to 1200 at idle and or when coming to stop (5 or 10mph) also sometimes at about 30 mph and climbing, it almost feels like a downshift but its not (rpms drop and rapidly climb back up) the engine light came on but before I could check the code, it went out. anyone have similar issue that can help? Thanks for your time.

Having a similar issue with my 2000 Bonneville. I have been monitoring it for the past few days, it just started on Sunday. No engine lights have came on.

Problem resolved. It was the mass air flow sensor.

Check for codes anyway. These PCM's will store history codes in memory long after the light goes out. Also clean throttle body and egr. If carbon is sticking either of these open a little, idle and low speed operation will suffer. Good luck

Clean your MAF and the IAC. People always forget about the IAC.

How do your vacuum hoses look? Cracked? There is a T under the nose of the supercharger also, check there.