1988 F-250 running rich

1988F250

MEMBER
1988 FORD F-250
V8
4WD
AUTOMATIC
100 MILES

I have a 88 f250 4x4 with a fuel injected 5L engine. The truck fires up fine but almOst immediately starts to run rich especially under load or higher rpm, I noticed the idle seems to pulse and the idle will drop down and some times even stall when the truck gets reved uP or put into gear. I have changed my fuel pressure regulator, cleaned my idle air control and bought an o2 sensor delete kit ( trucks got aftermarket pipes with no cats). Any suggestions on what I should change next would be awesome thanks.

Tuesday, May 31st, 2011 AT 2:16 AM

1 Reply

WRENCHTECH

MECHANIC
20,761 POSTS

You may have a bad IAC ( idle air control) but try eliminating any vacuum leaks and cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.

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Tuesday, May 31st, 2011 AT 12:14 PM