01 bullit mustang

[cezr75]

hey everyone
i own a 2001 bullit. i recently changed the iac valve on it and it ran good for a couple of weeks. now however the car idles at 900 rpms where as before it would idle at 750 rpms. i thought the iac valve had gone bad again so i took it back to the ford dealer and exchanged it. it is still idling to high. i also changed the tps sensor and still no change. any input would be apreciated. thanks everyone.

 

[Jbauer]

make sure all the vaccum lines and stuff are plugged in correctly and in the right spots..

try removing the battery cables for a half hour or so, then let the car idle for a bit without moving for a few minutes.. then drive it around for a few days and see if that helps too. ECM could need to re adjust again for some reason.

 

[cezr75]

01 bullit

hey jbauer,
well when i changed the iac i didnt mess with any vacumm hoses so ill try disconecting the battery for a while then let it idle. thanks bud

 

[trinity_gt]

While mucking about in that area, did you clean the throttle body or throttle plate at all?

 

[twogts4us]

I'd avoid cleaning the TB...the plates have a coating to prevent any build up of gunk...spraying the TB with cleaner can dissolve this coating.
Do you have a K&N Filter? If so, consider cleaning your MAF sensor. (There is a special spray cleaner for this...ck at the auto parts store (advance auto parts, auto zone both have it)

 

[trinity_gt]

I'd avoid cleaning the TB...the plates have a coating to prevent any build up of gunk...spraying the TB with cleaner can dissolve this coating.

Indeed, that's why I asked.

If the coating on the inside of the throttle body throat is cleaned away inadvertently, you can screw up the PCMs ability to properly control the idle because the loss of the seal allows excess air to bypass the IAC.

 

[trombonedemon]

Get yourself a catch can, yea, like Jbauer said, make sure all of your hoses are air tight using maybe a butane lighter, blow by can and will create idle problems. Try cleaning your intake manifold and your maf. I second disconnecting the battery. I refuse to oil my air-filter cause it screws with the MAF. It definitly sounds like your air intake at some point is dirty.

 

[cooter_11]

make sure all the vaccum lines and stuff are plugged in correctly and in the right spots..

try removing the battery cables for a half hour or so, then let the car idle for a bit without moving for a few minutes.. then drive it around for a few days and see if that helps too. ECM could need to re adjust again for some reason.

I think you're right on the money Jbauer. Sounds like the ECM needs to adapt to the new IAC. Drive it around for a few days and see if it goes away after you disconnect the battery first.