I NEED HELP REALLY BAD!
 

I've been working on my friends 90 gt for the past 2 days and i can't figure out what is wrong with it.It has a miss in it and it doesn't idle or run right.Ok so far we have changed the plugs,wires,cap,rotor bypassed the msd tried a different coil,tried a different mass air checked all the vacumn linesand still nothing also checked the timing.Does anybody have any ideas? could a map sensor cause this?control module?pickup coil?we need sugestions and we can't dump tons of money into parts he doesn't need.Also there is a hiss in the fuel line couls it be a bad regulator it does run rich.THANKS

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P.M.D. PERFORMANCE 88GT
306ci

How rich does it run? So rich that clouds of black soot and gas bellow out the pipes?

I wouldnt think a pick up coil. When they go, they usually GO. Theres usually not any half way running about it. A car with a bad pick up usually wont start.

Hook a pressure gauge to the fuel line and see what the pressure is.

Does the engine Ping at All?

Sounds like the stater inside the distributor. Happened to me a few years ago, seemed almost like a rev limiter when it got really bad. Started off as a light miss too.

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Dustin
89 GT(Saleen Clone) 392 rwhp UNTUNED(TFS Intake, spacer,Heads and #2 cam, BD-11A 9#(only boosting 6???WTF),1.6 rr's,BBK 70mm TB,FMS 70mm MAF,MSD 6BTM,FMS 9mm wires,BBK longtubes and H-Pipe,American Thunder cat back,3.55 lots more...

12.564@118.49 on street tires is my best so far. Still untuned

When's the last time he changed the fuel filter? I was beating my head trying to figure out a hesitation a week ago and it turned out to be as simple as the fuel filter. It had about 50k on it.

A rough idle could also mean a dirty IAB valve. Clean it out. It can also affect operation at cruise.

A stuck open EGR valve could cause such problems. You may want to try cleaning that out.

A fouled ACT sensor could cause this sort of problem.

If it's running rich, it may be bad O2 sensors. Have they ever been replaced?

Have you pulled your codes? The problem may be stored there.

Just some ideas.

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351W 89 Mustang GT Convertible

We hooked it up on a machine and it showed no problems.Something that is weird and might help desribe it is that it starts to smooth out when the car warms up a little.It doesn't go away completly but it gets somewhat better

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P.M.D. PERFORMANCE 88GT
306ci

I would bet on the Mass Air Meter. What is MAF does he have? What injector calibration?

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MAC equal length headers, MAC Off-Road H-Pipe, Flowmaster mufflers, 373's, underdrive pulleys, 76mm MAF, 65mm TB, TFS Track Heat Intake(ported & gasket matched), Edelbrock 6037 heads (ported, polished, 3 angle valve-job 255CFM @.500), 1.6 FMS RR's, Wolverine 1087 Cam, 30lb injectors, MSD 6AL, Subframe connectors, Griggs Adustable Lower Control Arms, Lakewood 50/50 shocks, SSM Upper Control Arms... and 8lbs of Procharged boost

Sounds like it could possibly be a clogged catlytic converter, or possibly a timing issue, like the distributor being off a tooth. Just my $.02

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87 GT, 4 inch cowl hood,17x9 Cobra R's/255/45's,GT-40 heads,Crane 2031, Edelbrock intake, long tubes headers,h-pipe,Flows,BBK cold air, Mass air,70mm MAF, 1.7's, 1" spacer,underdrive pulleys,Pro 5.0, King Cobra, Adj. fuel Reg., Lakewood Lift Bars,50/50's,subframes, 4.10's.
Best time 12.96
Best MPH 103.42
Best 60' 1.695

Visit my site at:
http://www.geocities.com/cobrar93_2000/MyPage.html

The ACT sensor is probably the only problem you would get a code on. Have you checked all the other posibilities that I already mentioned?

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351W 89 Mustang GT Convertible

Have you done a compression check?

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B.R.
L.X. 5.0 coupe
Cruise control,power mirrors,...and Thats it!

We did a compression test,fuel pressure check and still nothing.We did pull 2 plugs that were white.The car has no cats so that's not the issue.What or where is the act sensor?I know is a dumb question but i'm still new to the efi performance game

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P.M.D. PERFORMANCE 88GT
306ci

how rough is the idle? does the car stall?
any smoke from the tail pipes? did you or him removed the lower or upper intake any time soon?

I would check for a hose/vacum leak under the upper intake - follow that hose that connects to the BAP/MAP sensor.

Air charge temperature sensor. It screws into your lower intake manifold by the #5 intake runner. It's sticking out at an angle and is just forward of the plenum.

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351W 89 Mustang GT Convertible