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Discussion Starter · #1 · (Edited)
I have an 88 Gt with SD, i just put on new o2 sensors, cleaned the salt and pepper shakers, adjusted the tps from .15 to .9 volts (Couldn't get any higher), and put on a new IAC. The car idles 450 rpms lower when it is cold than when it is warm, so the idle is set at 1100 rpms. My problem is that it is running really rich, and won't rev past 4,000 rpms, the car loses power and stutters like it is hitting a rev limiter after 4,000 rpms:mad:.

Could my Egr valve need relaced? Any Suggestions?

Right now I want to push thing off a cliff. This car has been nothing but problems since I got it. I love Fords, I have seven of them, but this car is a pos.
 

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have you checked the cats? (if you still have them) I know then they get plugged, it wont rev like normal and seriously lacks power.
 

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this may be dumb but could your tach be off? I know mine is, I can rev it to 7k before it hits the stock rev limiter which is at 6250.
 

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First thing I'd check is timing and tps, verify those (you already checked the tps) then pull your h pipe off and see if it'll rev to 6k without cats
 

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Now Ive seen some sharp answers, hahaha you say stutter, running rich, meaning ignition breakdown, cats, all the above do not cause breakdown. Check your ignition module first! if that doesnt help PM me
 

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Now Ive seen some sharp answers, hahaha you say stutter, running rich, meaning ignition breakdown, cats, all the above do not cause breakdown. Check your ignition module first! if that doesnt help PM me
Youve clearly never had a car with clogged cats then. If they're clogged enough, they can absolutely cause the car to seem like it has no power. I had a car that would idle ok enough, but wouldn't rev over about 2500 and would take forever to make it up to speed. Cut the cat off and it ran like a dream.

Not saying I think this is a cat issue, but I wouldn't rule it out and I definitely wouldn't say cats couldn't cause an issue like this.
 

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Checking if they're bad is free so why the **** not check old man
 

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Does it do it when in nuetral and driving? only driving?

Mine would stutter real bad around 4k when i was driving. no codes. dropped the gas tank and the sump was broken free and flopping around. When driving the fuel when low would move away from the fuel pump.
 

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Re

Youve clearly never had a car with clogged cats then. If they're clogged enough, they can absolutely cause the car to seem like it has no power. I had a car that would idle ok enough, but wouldn't rev over about 2500 and would take forever to make it up to speed. Cut the cat off and it ran like a dream.

Not saying I think this is a cat issue, but I wouldn't rule it out and I definitely wouldn't say cats couldn't cause an issue like this.
you clearly didnt read my reply, he said the car is missing and stuttering, I have diagnosed several cars with clogged cats and your right they have a lack of power and wont rev to high rpms, but they do not miss and breakdown!
 

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So you've never seen a car with multiple problems before? Like I said, I don't think this is caused by cats, but it would be foolish to rule it out as a possible issue that the car has.
 

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So you've never seen a car with multiple problems before? Like I said, I don't think this is caused by cats, but it would be foolish to rule it out as a possible issue that the car has.
If the car is having issues breaking down, missing etc its a fuel/fire issue point blank, I'm terribly sorry your cats were clogged, and maybe his are, but from what he describes it has nothing to do with cats!
 

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Discussion Starter · #17 ·
Thanks for the responses guys, sorry that i didn't answer sooner. It will rev past 4,000 rpms in neutral, but not when driving. I will check my timing and pull my h pipe and see what happens. If that doesn't help what else should i try?
 

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Discussion Starter · #19 ·
Well i pulled my h pipe, and found that the pre cats are gutted, along with one regular cat. The remaining cat is not plugged, and a mechanic told me that it is having a fuel problem. Can i check fuel pressure by my self?
 

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I would get rid of that mid pipe then. Gutted cats are actually worse than cutting them out and replacing them with straight pipes.. But that won't cause the condition you're having.

You can check your fuel pressure with a gauge. You should be able to rent one at an auto parts store, if not they aren't that expensive to buy. Put the gauge on the schrader valve on the fuel rail, pull the vacuum line of the fuel pressure regulator and start the car. fuel pressure should be between 36-42lbs at idle with the vac line off.

When you say rev-limiter, is it actually missing when you hit 4k like how an actual rev limiter works? Or are you just saying it won't rev past 4k? If it is missing, then I agree with 57vetteguy, ignition side is where I would be looking first.
 
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