Hey guys, I'm new to the board and my name is Brandon. Getting down to business, I have a 90 GT which has an idle surging problem. I've changed the distributor harness, plugs, wires, distributor cap/rotor. My fuel pressure is right at 40. The car has 30# injectors with matching maf. Car has headers, heads, cam, gears, bigger alternator/throttle body/fan/intake system. Just a basic overview of what is done to the car. Just give me some things i could check in order to figure this out so i dont have to go spend more money that i dont need to for parts that i dont need. Any help is appreciated. Thanx
i would start out with the tps and throttle body adjustment's....
1st, with the engine off, take a feeler gauge (.010-.012) and underneath your throttle body, you will see a little adjustment bolt, back that off till you feel a slight drag between the bolt and the throttle body linkage......with that done, we will check the tps voltage.....turn the key on, engine off, take a needle and stick it into the green wire....use a volt meter and check your voltage......should read .096.....if not, you will need to barely loosin the two phillip screws and find .096.....tight down the bolt's, start the car and see how she feels......
hotwheels of insanemustangs.com
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My first thought is vaccum leak. Some people tell you to spray around your lower intake with carb cleaner or better yet some air intake cleaner which is formulated to not hurt any of your sensors. I had a leak at my lower intake front or (more likely) rear seals. I had used those crappy rubber gaskets that come in the set. They suck, dont use 'em if you havnt already. Just use a real thich bead of silicon. Since you have done an aftermarket intake (correct me if Im wrong) you are a very likely candidate for this. Also, when my TPS broke, I had a horrible surging idle, check to make sure the TPS is springing back. I had a brand new one break in only 1 week of use. How bad is the surge? That can probably tell us a lot. Good Luck
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Cardinal Red '88 GT 5 speed, Cobra Upper/Lower, Dynomax complete Super-Turbo cat-back system, Turbo Coupe Rear 10" discs, 3:73 gears, SN95 Master Cylinder, Summit Racing adjustable proportioning valve, Spec Stage II kevlar clutch, steeda adjustable cable/quadrant, 73mm front calipers, P.A. Performance 130 amp alternator, 99 Contour Electric Dual Fans, Battery relocated, rebuilt 91 T-5, Mass Air conversion
Thanx guys, i'm gonna give some of this a shot. I know a guy, friend of the family, that has 3 fox bodies and im gonna see if he can pull some **** off his car and see whats the deal with mine if i cant figure it out. throw him a few bucks and so forth. I mean he's a mechanic, but it's pulling apart his car lol. Eh, whatever, i'll find out soon. Again, i appreciate your help guys, esp for the n00bie haha
Thanx guys, i'm gonna give some of this a shot. I know a guy, friend of the family, that has 3 fox bodies and im gonna see if he can pull some **** off his car and see whats the deal with mine if i cant figure it out. throw him a few bucks and so forth. I mean he's a mechanic, but it's pulling apart his car lol. Eh, whatever, i'll find out soon. Again, i appreciate your help guys, esp for the n00bie haha
Well I took it to a friend of a friend to see if he could help me out with the idle problem, so i take it to him and its still doing its thing, and he, luckily for me, had a TPS just chilling in his garage. So we throw that bad boy on there and it still idle surges.. hmmmm. So we decide to unplug the maf and whooptie fuckin doo it idles perfect. So in the end, i needed a maf definately, and i'm sure that TPS didn't hurt either.
Also, i picked up another fox body today. A 90 notchback with a 351 in it. I got an MSD box with it so im gonna put that in my car and probably do a little tuning on the 351 (it's carbed and is running rich as ****), then give it to my father. I'm sure he'll like it, carbatutors are his forte anyhow. So win win situation, i get some cool **** for my car and my dad gets a little project for him to have fun with
All in all it looks like it's going to turn out good so i'm happy about that, i appreciate everybody's help and maturity on here, can't find that in very many places, im sure ill be calling on this forum in the future for more advice and to shoot the shits with ya. thanx
Could possibly be your IAC on it's way out as well ,if it still continues after you change the MAF. It sits right on the throttle body. Mine was surging as well and I changed the TPS and still did it well I changed the IAC today and it no longer surges at idle or dies when it is warm.
Drew
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If I take cars and hot girls with money and add them to my life, I have found the key to happiness!
87 GT (UNDER CONSTRUCTION) new paint job, 306 w/ TFS stage 1 cam, TFS intake , still cant decide on heads.
Thanx for the input, but i've already had that changed. I got the new maf on and it works great but the damn shaft on the butterfly in the throttle body snapped so now i gotta get that fixed, could possibly be part of the problem as well. After the throttle body is switched out that should be the end of this dilemma. I enjoy working on it anyway.. fun ass car to drive, that's for sure. Thanx again.
Idle Surge Problem 
