[cpgray]

I have a 2001 GT with a manual transmission and a K&N air intake. Recently, I have been having trouble with the engine returning to idle after I take my foot off the gas. The engine will actually surge and the delay can be as long 5-10 seconds. If the air conditioner is on the delay is even longer. I took the car to the dealer for a diagnostic check and there were no error codes. they said the car would have o be returned to stock before they could check further. I suspect it could be the mass air sensor but I'm looking for any suggestions.

[EagleAutosports]

Hiya and welcome. Glad you joined us.
I'll move this to the 4.6 tech so it'll get the best exposure for your problem.

[gnr_70]

Originally Posted by cpgray

I have a 2001 GT with a manual transmission and a K&N air intake. Recently, I have been having trouble with the engine returning to idle after I take my foot off the gas. The engine will actually surge and the delay can be as long 5-10 seconds. If the air conditioner is on the delay is even longer. I took the car to the dealer for a diagnostic check and there were no error codes. they said the car would have o be returned to stock before they could check further. I suspect it could be the mass air sensor but I'm looking for any suggestions.

It could be the IAC. I had the same issue with my 00 GT.
1. Remove the IAC and visually inspect it.
2. Spray the inside with a brake cleaner or carb cleaner. You'll see soot buildup. Clean it as much as possible. Let it dry completely then...
3. Reinstall the IAC, start the car.
4. Observe the car for a few days.
5. If same issue arises, replace the IAC.

Hope that helps.

[CobraBoy]

you have been messing with your air intake? how about your throttle body?

i would suspect more your throttle position sensor

[cpgray]

Originally Posted by gnr_70

It could be the IAC. I had the same issue with my 00 GT.
1. Remove the IAC and visually inspect it.
2. Spray the inside with a brake cleaner or carb cleaner. You'll see soot buildup. Clean it as much as possible. Let it dry completely then...
3. Reinstall the IAC, start the car.
4. Observe the car for a few days.
5. If same issue arises, replace the IAC.

Hope that helps.

Thanks for the info.....I'm afraid I'm not familiar with the acronym "IAC"....Hopefully it will help...

[cpgray]

Originally Posted by CobraBoy

you have been messing with your air intake? how about your throttle body?

i would suspect more your throttle position sensor

I haven't touched the throttle body or the air intake since I put on the cold air kit a couple of years ago...I had a suggestion it could be carbon or soot build up in the IAC (what ever that is!) Thanks fo you help

[cpgray]

Originally Posted by cpgray

Thanks for the info.....I'm afraid I'm not familiar with the acronym "IAC"....Hopefully it will help...

I replace the Idle sensor control and that seems to have solved the problem. It would appear this is one of the more common problems with my year...too bad the mechanic at the dealer didn't know about it! Thanks for your help.