'99 Mercury Grand Marquis Rough Idle/Stalls

I have a '99 Grand Marquis recently it started have problems at idle. Sometimes it idles but it feels like it is idling below its normal idle speed. When driving it doesn't have a problem at any speed, however, occasionally when cornering it will die. The check engine light has not come on (other than the normal times when starting or restarting). I had the codes checked anyway and as I expected I set a code of P1507 because I have been keeping my foot on the accelerator to keep it from dieing at idle. Any suggestions would be greatly appreciated.

Reply to
lmcsween
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IT sounds like tha IAC is dirty. Many times they can be cleaned and reinstalled after soaking in throttle body cleaner for a while followed by a good spray dousing. While you are at it, it would be a good idea to clean the MAF sensor and the EGR ports in the manifold. The IAC will not normally set a fault code just because it is dirty. It can also cause hard cold starts and no high idle when cold as it should be.

Lugnut

Reply to
lugnut

IAC valve.

Almost 100% sure. May be crapped up, may be shot. Just had exact same thing last week on my Vette. Ran rough for a long time before it gave out. Pintle all carboned up.

-GeorgeC

Reply to
George Csahanin

Im with these guys, had to clean it on my 98 CV and my 2000 GM.

Reply to
chris

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