I have a 2002 Galant that idles and drives great. The problem is that when slowing down for a stop, the idle drops to 500 RPM and then about a second later it climbs back to around 800 or so. It feels like it is going to stall out but it doesn't.

No CEL or codes.

Any ideas?

Thoughts:

. Try cleaning the throttle plate, throttle body, and Idle Air Control Valve (IACV) with spray cleaner. Tap the IACV with a screw driver plastic handle. If the stepper motor starts to work better, replace the IACV.

. Evaluate if you feel the MAF Sensor and/or connector is part of the problem. Sometimes, this takes an advanced scan tool that can show pending codes.

I was wondering if it could be the IAC.

This is a car that I am putting out for sale so I haven't driven it much. I replaced the battery today and then drove it and I noticed the problem. Could it have something to do with the ECM needing to relearn idle?

Have you tried setting the idle rpm from scratch?

Have you tried setting the idle rpm from scratch?

You've lost me. I stopped working on cars "professionally" back in '97. I have been out of the car business since then and only worked on my own cars. Now I have a used car lot and try to do the work that I can do myself rather than pay someone.

How would I go about setting the idle from scratch?

You need to read the Shop Manual, or other source, about how to do it. Sometimes, the IACV is disconnected and then the idle rpm is set, for instance. I've seen on some Hondas where if the idle rpm is not set properly, the A/C will not blow cold air at idle. Locate the idle rpm adjusting screw and find out what rpm it should be adjusted to.

Ok, thanks. I will look into it.

Thanks for the help.

Problem solved.

When I got the car, the rear engine mount was bad. I replaced it and then went through this issue that I posted about. Long story short, I found a wire rubbed through from the engine tilting due to the bad mount.

I repaired the wire and it seems to be fine now.