2001 Chevy Prizm
When I come to a complete or near-complete stop and then step on the accelerator, the RPMs fall and the car seems like it wants to stall. This is just for a split second and then the car takes off. I’m a “spirited” driver. I don’t mess around when I want to go.
If I slowly press the pedal down, the problem is greatly diminished, or possibly even non-existent.
It’s been to the dealer twice so far. The first time they replaced the fuel filter and cleaned the throttle body. No effect.
The second time they said the catalytic converter was clogged. I had it replaced and it helped considerably. Before this the car would actually quit sometimes, but that has seemed to stop.
I replaced the plugs.
I have a vacuum gauge and the vacuum at idle seems normal. I didn’t do a lot of testing with it. I can do more, but there wasn’t an obvious leak.
I don’t really have any other symptoms. The car idles ok. It drives fine otherwise.
Even before the catalytic converter was replaced and the car would actually die the Check Engine Light has NEVER come on. Not ONCE!
For my next step I was going to attempt cleaning the MAF with electric contact cleaner.
Any other ideas?
Thanks!
I’d be really careful about what you squirt into the MAF. I think there’s actually cleaners that state on the label that they can be used in a MAF/AMM.
Well I had a CRC Electric Contact spray can already, AND I didn’t know about that stuff 
Seeing as how the MAF sensor is basically a wire with electricity flowing through it seems like a good match, but yes, I looked and they do make specific MAF spray. I appreciate your concern and will probably pick up a can next time I’m at the parts store.
For those interested, I looked at the MSDS sheets for CRC MAF spray and CRC Electric spray. The main ingredient of the MAF spray is “hexane isomers” and the electric spray is “isohexanes.” Hmmm, seems suspiciously similar, but hey, I’m no chemist. They are probably significantly different.
Anyway, it WORKED. Two screws, two squirts and less than 10 minutes of labor total. All vestiges of my problem are GONE. My car accelerates with no hesitation, just like when she was a young pup. It even starts quicker. I apparently hadn’t noticed the gradual increase in cranking time over the last 10 years. I will post back in a week or so to let you all know if anything changes.
I don’t have a idea yet as to the cause of your “low idle” “hesistation” ,do I have the description right? What I do have is a comment on your observation that replacing the cat on your car fixed a stalling problem. Cats when they are plugged exibit symptons such as real low power (wont go over 20mph but would idle fine).
Great! You cleaned the MAF (Mass Air Flow) Sensor element, and it fixed several problems. The catalytic converter was, probably, burned out from too much unburned fuel going to it because of the contaminated MAF Sensor. It should now last its normal life span, if the engine is maintained.