ChalknCover

Okay, this just recently started. When I start it up and put it into gear (auto) the engine revs b/t like 500-1200 rpm, but once I use the gas, it goes away and sometimes at a stop light it drops from 1000 to 500 rpm. Is this just a case of the MAF needing to be cleaned, or is there something else I need to look at. The problem isn't constant and it doesn't do it everytime, just have noticed it lately. Also, I have been driving it more since my DD Exploder decided to let a cat fall apart.