idleing problems - Northern California Ford Owners

This is topic idleing problems in forum Tech Talk at Northern California Ford Owners .

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Posted by 73beast351c (Member # 5397) on :

hey i just got a 89 convertable with a gt 40 crate motor and 24 lb injectors with a calibrated mass air flow. It runs pretty good the only problem i have is when it idles sometimes it spikes a little up and down (between 400 and 900 rpm) and then shuts off. Im thinking it might be the trottle body it looks like stock size it has a cobra intake so i know that can handle it. And when it idles right i can rev it up a little bit like to rev at someone and when i lett off the car with spike again and shut off from there. Maybe it needs a tune or something any suggestions

btw: specs
1. Gt 40 Crate motor 345 hp
2. 24 lb injector and mass air
3. Orginial 93 cobra intake from ford
4. bbk cold air intake
less then 5000 miles on all these parts

Thanks

Posted by Blind (Member # 3052) on :

I would remove and clean out the IAC motor/valve and then do a complete idle reset procedure, I don't have a link to post but if you google for it or do a search on corral.net forum I'm sure you'll find it.

Posted by BlueLightning302 (Member # 3974) on :

i had that same exact problem, tried several different IAC's, nothing worked. I ended up drilling a small hole on the TB plate, never died or had that problem again. First make sure you dont have any vacuum leaks, then i would try that.

Posted by 73beast351c (Member # 5397) on :

ok i'll check the iac at work today. Would getting a bigger trottle body by fix it. And what size hole did you drill. Thanks

Posted by BlueLightning302 (Member # 3974) on :

i think 3/16's or so. what cam does that longblock come with?

Posted by Blind (Member # 3052) on :

personally I installed the ford racing adjustable idle plate instead of drilling my throttle body, I have a edelbrock 65mm on an edelbrock intake and it did the same idle hunting until I got that plate in there to give the motor more air at idle.

Posted by 73beast351c (Member # 5397) on :

yeah thanks for all the help blind lightning it solved the problem. Yeah the whole reason the guy sold the car was because that problem. So yeah if you go to the gallop around the bay cruz i'll buy you a coke or something

Posted by BlueLightning302 (Member # 3974) on :

haha thats good that it worked out!

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