GenVibe - Community for Pontiac Vibe Enthusiasts

I have an 05 base auto with 220k. My daughter drives is now and she had a problem with the battery dying. As it was 3 years old I went ahead and replaced it. On installation of the new battery I noticed a problem. When I first started the car it high idled normally and was reading 14.2v on the battery. After the engine warmed up the idle went down to about 800rms as normal. Voltage reading was againg 14.2v. I let the car idle for 10 min and everything was fine. When I went to drive it around the block the idle would go down to 400 to 500 rpms at a stop. When I brought it back and checked it the voltage was down to 12.1. Thinking I had a alternator problem I replaced it and the serpentine belt. Car acted just like before. No CEL
lights are comming on. The car acts like it wants to die but runs fine when you get going. Seems like the car thinks it is suppose to idle that low. Maybe some sensor is not reading correctly. Anyone have any ideas? Thanks

Update, went back out and cleaned Maf sensor and throttle body with intake cleaner. Seems to have resolved the issue. Never cleaned the throttle body before. 220000 miles of gunk must have caused the plate to stick a bit, throwing the computer off. Took it out on the highway and seems to idle normal now.

I have experienced the EXACT same symptoms in my 2005 Base at least twice after disconnecting the battery for longer than a few minutes! I chalked it up to the computer re-learning its (removed) from a hole in the ground. Like yours', mine idled normally immediately after restart, but then low-idled later. Situation always self-corrected within a day.
chiadog

Thanks for reporting back. Too bad you had to replace the alt and belt but after 220K miles I'm sure it was due.

Throttle body cleaning is one of the things I recommend to do every 100k miles.