excessive idle on '89 302

pablo99 · #1 12-10-2003, 11:27 AM

Greetings all. I have an 89 f150 with a 302, automatic and all stock with 160k miles. When I first start the engine, the idle goes to at least 2500+ rpm and doesn't back down until of course the engine warms up. At first, I thought it was the air bypass idle control valve so I replaced it and the only positive news was during deceleration. Next, I check the TPS and it appears fine.. .9v at idle and 4v at WOT. Next, I pulled a code of 33 which points to the EGR but I'm not sure how that could affect the idle. Any help would be appreciated. Thanks in advance.

Obie05 · #2 12-11-2003, 06:20 PM

Hi, Perhaps you should investigate the possibility of an intake manifold leak. If there is air bypassing the throttle plate (other than the air that bypasses at the idle control valve.) it may case this type of problem. Is that 302 a 4,9l inline?

pablo99 · #3 12-13-2003, 02:45 PM

Quote:

Originally Posted by Obie05

Hi, Perhaps you should investigate the possibility of an intake manifold leak. If there is air bypassing the throttle plate (other than the air that bypasses at the idle control valve.) it may case this type of problem. Is that 302 a 4,9l inline?

Thanks for the reply. It is a 5.0 v8. I wound up replacing the EGR valve and that didn't help at all. As a matter of fact, the check engine light comes on now. I guess I should check the new egr with a vacum pump and then pull some codes again.