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roy
roy, import/domestic specialest
Category: Ford
Satisfied Customers: 4657
Experience:  ASE master tech for 40 years
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1989 F150 5.0 L ENGINE. When starting engine cold RPM's go

Customer Question

1989 F150 5.0 L ENGINE. When starting engine cold RPM's go up to 1800 rpm then after warms up idle's about 100 rpm. Have replaced IAC, EGR, checked for Vacuum leaks. Pulled hoses from throttle body and placed hands over both intakes, no change in idle speed.
JA: How has your mileage been lately? How long have you had the leak?
Customer: Worse than usual. I have had the problem for about two weeks. I was driving down the road and the engine starting to make a roaring sound and ever since then I have had a high idle problem
JA: What is the model of your '89 Ford?
Customer: F150 XL 4 x 4
JA: When was your last tune up?
Customer: About two years ago. Truck only has 71,000 original miles. Did tune up at 65,000 miles
JA: Are you hoping to fix this yourself?
Customer: Do you need any other info?
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Ford Mechanic about your situation and then connect you two.
Submitted: 6 months ago.
Category: Ford
Expert:  roy replied 6 months ago.
good afternoon my name is ***** ***** I will assist is this carb or fuel injected?? Roy
Customer: replied 6 months ago.
fuel injected
Expert:  roy replied 6 months ago.
ok, on top the throttle body is an idle air control valve. it is a very common failure for this condition. remove the 2 wire connector and see if it drops to base idle. in your post you said 100 rpm but the engine will not idle at that .I assume you meant 1000 rpm Roy
Customer: replied 6 months ago.
I did replace the IAC did not change any symptoms
Customer: replied 6 months ago.
Sorry I meant 1000 rpm's
Expert:  roy replied 6 months ago.
ok, when you remove the wire connector, what happens??? what rpm??? Roy
Customer: replied 6 months ago.
no change in idle speed at all
Expert:  roy replied 6 months ago.
ok, there is a base idle screw on the throttle body for the throttle plate. can you see if the linkage is resting against that screw Roy
Customer: replied 6 months ago.
it is
Expert:  roy replied 6 months ago.
then you need to loosen the screw to lower the base isle to 500 rpm. do this with the connector off the IAC motor Roy
Customer: replied 6 months ago.
I will do that, does the screw get out of adjustment often?
Expert:  roy replied 6 months ago.
it should not. there should be a spring around the screw that keeps it in the same position Roy
Customer: replied 6 months ago.
Ok I am at work and have no tools to adjust screw, will do when I get home. Thanks.
Expert:  roy replied 6 months ago.
please dont forget to rate me as it is the only way I get paid for my efforts Roy
Expert:  roy replied 6 months ago.
ok
Customer: replied 6 months ago.
not a problem
Expert:  roy replied 6 months ago.
thank you
Expert:  roy replied 6 months ago.
please dont forget to rate me as it is the only way I get paid for my efforts Roy

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