Hi, I have a honda civic 2001 prosmatic. It runs just fine but when the engine warms up the engine…

Hi, I have a honda civic 2001 prosmatic. It runs just fine but when the engine warms up the engine drops the rpm from 800 to 500 on D and R and jumps back to 1000rpm when I put it in P or N. I have cleaned the IACV and throttle but the problem still remains.

We call that a Civic in Canada - good car - I'd say scan the car's computer for fault codes and lets start from that point to diagnose - also given it's age I'd be changing out most of the vacuum hoses since they may be causing a small vacuum leak - check very closely

Try this video of Scotty's, if no MAF sensor, ignore that part of it:

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