2003 Explorer rough RPM deceleration

[natelunt]

My ford explorer started stalling out at idle so I replaced the IAC which fixed the idle situation, but now my engine does not decelerate smoothly. When slowing down the engine hangs up at about 2000 RPM for a bit then abruptly drops down to normal idle speeds. This causes a bit of a jolting slow down and stop. Any help would be appreciated. My local mechanic is stumped and he has been working on various solutions for a week but nothing has helped. The situation does seem to get better after warm up.

 

[07gtman]

Do you have a check engine light on? if so get the codes

 

[natelunt]

No check engine light.

 

[Mickalo]

did you happen to check your throttle cable or throttle body (i assume you don't have throttle by wire) setup.

 

[07gtman]

did you reset the computer after iac was installed, though it may be the egr

 

[cj1972]

My ford explorer started stalling out at idle so I replaced the IAC which fixed the idle situation, but now my engine does not decelerate smoothly. When slowing down the engine hangs up at about 2000 RPM for a bit then abruptly drops down to normal idle speeds. This causes a bit of a jolting slow down and stop. Any help would be appreciated. My local mechanic is stumped and he has been working on various solutions for a week but nothing has helped. The situation does seem to get better after warm up.

Did you install a Motorcraft IAC? I had (what sounds like) the same problem on my truck. The fix was replacing the new BWD brand IAC with a new Motorcraft IAC. It hurt my wallet because it ended up at a dealer to get the problem fixed.

 

[07gtman]

cj1972 is right about about the motorcraft parts

 

[natelunt]

What's the right way to reset the computer? I disconnected my battery for a few hours but that didn't help. I did use the standard IAC from oreilys. I replaced the first one with another new one, but the same brand, because it was originally much worse. The new one helped but its still not completely better. Maybe I should try the other brand.

 

[07gtman]

you may want to try and drive for 40 or 50 miles to see if it will throw a code ,this will put you in a better direction as to the real issue is, instead of just throwing parts at it...have you gone threw the vacume hoses

 

[cj1972]

What's the right way to reset the computer? I disconnected my battery for a few hours but that didn't help. I did use the standard IAC from oreilys. I replaced the first one with another new one, but the same brand, because it was originally much worse. The new one helped but its still not completely better. Maybe I should try the other brand.

Take the IAC and shine a light into it. If you see light coming through it, I would really consider buying a Motorcraft one. (The service writer at the dealer said the tech did this to determine that my [new BWD] IAC was bad.) I hope that helps.

 

[natelunt]

Thank you for everyone's advice. I replaced the IAC with the motorcraft one and it immediately started running right. Best Regards.

 

[cj1972]

Thank you for everyone's advice. I replaced the IAC with the motorcraft one and it immediately started running right. Best Regards.

I'm glad to see that it's running right. I know how frustrating and expensive it was when my '02 F150 had the same problem. It's upsetting when a new part doesn't work or doesn't work correctly. I went without my truck for a few weeks so I understand what you had to deal with.