Question about 1991 Pontiac Grand Prix

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Poor acceleration while trying to pass and check engine light on

Ok, so I have a 91 Pontiac Grand Prix GTP 3.4 V6. The check engine light comes on. I used the OBD1 to check it and it spits out the code 32 which is the EGR system code. I replaced the EGR and gasket. About two weeks later, the engine light came on again with the same code. The car idles fine, runs a little loud, my main concern is the lack of power and erratic surges it has while it accelerates. It really struggles when it is between 2500 and 3500 RPM's. Once it passes 3500 RPM's, however, it really gets going. There IS a hose that isnt attached to anything and i cant find anywhere to plug it in. I need some advise. Any advise is welcome.

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  • Tony Kron Apr 24, 2009

    I dont know a whole lot about cars, so please bear with me. I believe the hose is coming from the manifold, i followed it around to the passenger side of the engine, it connects somewhere between the belts and the block. Im not sure how to check for leaks. Could you explain? I tried plugging the hose with my thumb but couldnt really feel any vacuum, it did however start to smoke a little and it smelled like gas fumes. As for the noise, its only noticeable when accelerating and is kind of a knocking sound.

  • Tony Kron Apr 27, 2009

    Ok, well i looked up all the hose diagrams. i found where the mysterious hose goes. but the power brake booster hose is plugged in there. i currently have a T valve piece to connect both the power brake booster and the emission hose to the same nipple. It has cut down on the brake power, so its a little harder to stop. Is there any other way to do this? I think the best way to describe the loud engine sound as a rattle. Cant tell the origin of the rattling though.

  • Dale Long May 11, 2010

    Double check the hose location, If you have to change the connector, it doesn't belong there. The Brake Booster should have a larger hose going straight to the manifold vacuum. The noise is more than likely spark knock, it's internal. That means it is not firing at the correct time. Or it could be a number of things??

    Put the brake booster back the way it was before you have brake problems too, or an accident. Without the booster assist, it could be difficult to press the brake pedal.

  • Dale Long May 11, 2010

    Could be spark knock? Get a good repair manual for the car and find the vacuum diagram. That will tell you where the hose goes and a good place to start.

  • Dale Long May 11, 2010

    Have you checked for vaccum leaks? Does the mysterious hose have any vaccum while the engine is running and where is it connected? I.E. it has to start from somewhere, trace the origin.

    Runs loud? please clarify--engine noise, exhaust, ???



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You said it struggles between 2500 and 3000 RPM. checking the hose for vaccuum at idle won't work. Rev the engine to the problem RPMs and check. That will tell you about vaccuum. As for where it goes, it won't go in the same palce as the brake booster. There will be another connector. If the re is a T there now, it sounds like someone else may have changed things around.

Posted on Sep 14, 2009

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I would check to see if that hose has any vacuum by placing your finger on the end to feel for vacuum.also,where is the hose located? behind the engine?? there are vacuum lines/hoses that are involved in controlling the egr valve,not just the egr valve itself. follow the vacuum line back from the egr to see where it goes.make sure all those plastic lines/hoses are not cracked or disconnected. also there should be a white sticker/decal under the hood probably near the radiator or by one of the strut towers that will give you info on spark plug gaps,VACUUM LINE POSITIONS,ETC. that should tell u where the disconnected hose goes-that MIGHT be your whole problem.let me know if this helps.

Posted on Sep 03, 2009

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Your loose hose from the EGR might plug into the back side of the throttle body...I'm not sure of the 3.4 liter setup.

Posted on Jun 23, 2009

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