Hey guys, so I have this weird problem where my rpm bounces. It happens in all gears but its most noticeable in 1st gear. When I let go of the throttle and the RPM meter goes down to 2000 RPM, the meter drops immediately to around 1000-1200 RPM and bounces back up to 2000 RPM. Remember I have my foot off the pedal the whole time. When this happens, the car slows when it drops and then jerks forward when it bounces back up. I have no idea what the problem could be.

I also have a service engine light on with a code of p0507 idle air control system RPM higher than expected. Could it be a vacuum leak? Does this tie in with the weird RPM bounce? Would it be best to bring it into the shop and have them fix it or it's easier and cheaper to DIY.

Lastly, At around 3000-4000 RPM in 1st and 2nd gear, I hear a whistle noise coming from under the hood.

Thanks so much!

 

Vacuum leak sounds likely. Shops can use a smoke machine to quickly find a small vacuum leak, if in fact, that is the issue.

Quite a few people have mentioned the whistling noise under acceleration in 1st and 2nd, more audible when the windows are down.