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Discussion Starter #1
Hello All,

I have a 94GT that i recently installed a MAC Off road H Pipe and an Edelbrock cat back exhaust and a MAC cold air intake.

But i am now having a few problems that i was hoping saomeone heere might be able to shed some light on.

First of all there is a pipe and branches out and connected to both of the factory Catalytic Converters and ran into the engine via a 1/2 inch metal pipe. I am told this is some sort of scavenging pipe to reuse unburned gas in the exhaust gases. Well i had some trouble getting it out and eventually just cut it out so that i could disentangle it. After connecting exhuast i just ended up plugging this pipe on either end for now as i did not have the pipe clamps necessary to get it back on.

And i am having a couple problems and was wondering if they are related to this scavenging pipe or something else.

First the Check Engine light is comming on whenever i apply moderate pedal and stays on for a while then trips out again. I did reconnect the Oxygen sensors and they seemed fine so i don't think they are the problem. And before any one suggests it this is a 94 GT which unlike the 96-02 V8's doesn't have rear O2 sensors so MIL Eliminators do not seem to be the answer. I did get a pair of them but when i asked the manufacturer about the fact that mine was a 94 her said send it back and that i probably had an exhuast leak.

The second problem is remarkably decreased gas mileage. First of all this engine does need to be rebuilt/replaced as it DOES burn a LOT of oil but i was getting 225 Miles out of a full tank before the exhaust/Intkae changes but now i'm lucky if i get 140 mile sout of a tank. Would that scavenger pipe have THAT much effect on the mileage? Or is it maybe that the engine is breathing better with the cold air pipe that it is just burning more fuel? Any input or suggestions would be much appreciated.

TIA
Mikey
 

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I think that the scavanger pipe is your problem. If the check engine light comes because of this your engine goes int a limp mode where it runs rich and kind of crappy. If you hook the pipe back up then disconnect your battery for a few minutes the computer will reset and it should be fixed.
Good Luck
 

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I am sure that little pipe is contributing to your problems, if those computers dont get the info from the sensors they are looking for they will run crappy and or get poor fuel milage because of the insuffieceint or missing data. I had to cut the same metal pipe in my mustang, I reconnected it with a piece of rubber hose and hose clamps, it worked great and the car wont know the difference. You can clear the codes in your computer after the fix by disconnecting the battery for a few minutes.
Hope this helps you out and gets you back on the road till you can slap that bad ass 347 in it that you know you want.
 

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Discussion Starter #4
Ahh, i thought maybe that was the problem, but thanks for taking the time to tell me.

 
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