91' Trans Am massive vacuum leak(I think)
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Junior Member
Joined: Jun 2009
Posts: 3
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From: Dublin, Ohio
Car: 91' Pontiac Trans AM GTA
Engine: 305 TPI 5.0L 8 cyl.
Transmission: Standard
91' Trans Am massive vacuum leak(I think)
Ok so i have a 91 Pontiac trans am. The engine is a 305 TPI, and I am pretty sure there is a massive vacuum leak and i have no clue as to where it could be. I have replaced the fuel filter and a brand new fuel pump is in the tank(that was a pain). I recently have started the car up after putting in the fuel pump and noticed that it was ideling high. Then revving the engine up causes the car to bog down and almost die if i dont release the gas. I have taken off the throttle body to free it up because it was sticking then put it back on. So i was wondering if maybe this was a common inssue and if it is an easy fix or not.
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Joined: Feb 2000
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From: Schererville , IN
Car: 91 GTA, 91 Formula, 89 TTA
Engine: all 225+ RWHP
Transmission: all OD
Axle/Gears: Always the good ones
Re: 91' Trans Am massive vacuum leak(I think)
Did u get the throttle body service kit from the dealer with new gaskets and the like?
Does the IAC seal properly?
Did u mess up the TPS?
I cant see it so I can only ask questions
Stick a vacuum gauge on it and see what it does.
Does the IAC seal properly?
Did u mess up the TPS?
I cant see it so I can only ask questions
Stick a vacuum gauge on it and see what it does.
Last edited by 3.8TransAM; Jun 13, 2009 at 11:57 AM. Reason: I spelzed something badz
Thread Starter
Junior Member
Joined: Jun 2009
Posts: 3
Likes: 0
From: Dublin, Ohio
Car: 91' Pontiac Trans AM GTA
Engine: 305 TPI 5.0L 8 cyl.
Transmission: Standard
Re: 91' Trans Am massive vacuum leak(I think)
well i did not have any new seals for the throttle body because i just was trying to free it up so i put it back on and it set fine. I did not mess with the TPS.
The first time this happened was when i just went out to start up the car. It started up fine, but when i went to rev it up it just bogged down and there was some black smoke. this was after it started up the day before. I sprayed some carbon cleaner around to see if it would rev up and somewhere towards the back left of the engine was a leak. But i cant seem to figure out anywhere back there that the engine could be getting air from.
The first time this happened was when i just went out to start up the car. It started up fine, but when i went to rev it up it just bogged down and there was some black smoke. this was after it started up the day before. I sprayed some carbon cleaner around to see if it would rev up and somewhere towards the back left of the engine was a leak. But i cant seem to figure out anywhere back there that the engine could be getting air from.
Thread Starter
Junior Member
Joined: Jun 2009
Posts: 3
Likes: 0
From: Dublin, Ohio
Car: 91' Pontiac Trans AM GTA
Engine: 305 TPI 5.0L 8 cyl.
Transmission: Standard
Re: 91' Trans Am massive vacuum leak(I think)
well i found out the problem, it was the damn EGR valve. The thing was stuck open and causing the vacuum leak. After that was freed up i turned the key and it cranked over instantly. It idled perfectly fine for like 2 mins and i revved it up with no problems but then out of nowhere it croaked and wouldnt start back up. I am thinking that it might be the control module now because it wouldnt fire with ether but then again the ether wasn't coming out in a spray but a stream.
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