December 24, 2005Hey guy's. I got a 1989 ford 150 custum with EFI 302 small block v8, the truck used to idle at about 800rpm when warmed up but now its idling at 2500rpm. I tried pulling the battery out for a day to reset the computer. It ran normal for about 20 min then went back to ilding at 2500rpm again. I got no clue when it comes to EFI any one got any ideas on what the problem could be?
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December 28, 2005Check for a vacuum leak, if not then maybe the IAC motor (Idle Air Control) is bad or sticking .....
June 12, 2006Ok run the engine and unplug the IAC sensor if that does nothing the sensor is bad or the wiring is bad. Pull it off and shoot it with carb cleaner push the plunger in a couple of times through it back on.
If it idles now it is just sticking replace it.
If this does nothing try the TPS throttle position sensor. Same deal, different sensor
check the throttle linkage from the pedal to fuel plate and make sure nothing is hitting.
Also look at theIAC sensor's mounts as well as the screw to make sure they have not moved from stock.
The engine should not run with a vacume leak that whould cause a idle that high unless the MAP maniflod Absoulte pressure sensor is bad.
Just unplug em and see what happens the TBI sensors are very forgiving.