turbomattk

Not accelerating at 4000rmp

15 posts in this topic

I have a 2002 Pontiac Grand Prix 3.8 45k miles. Recently I have noticed that whenever I go above 4000 rpms the car quits accelerating and makes a puffing sound from the engine. Tonight I found out that the car will not go above 90mph and it is hard to accelerate at higher speeds and the service engine light came on when I tired this on the interstate. I have put fuel injector cleaner in the tank twice but it has no effect. You can not notice a problem with the car when driving normally on city streets and the car still gets around 22mpg. I want to fix this myself so I don't have to take it to a shop or the dealership. Thanks!

-mk

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if the check engine light is on you can go to autozone and get a free diagnostic check and if its a part that they sell, well you can buy it and fix it.

Im not sure but somtimes a code will stay on the computer even if the light is not on for a specific amount of time.

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sounds like what happened to my impala. started out like that and progressivly got worse until one day i could only do 60 on interstate and it had a hard time getting going at stop lights, ended up being the catlytic converter....went out on my impala at about 70k. I would say take it to your dealer though, becuase if it is your catlytic, then you have emissions warranty until 80k and it would be covered under that. They did all the work on mine for free. Plus, since your check engine light came on, the dealer can hook it up to the puter and tell you what is wrong. It will prolly cost you $40 or so to have them do that but once you find out what is wrong, you can decide what you want to do about it, fix it your self, have them fix it or take it somewhere else.

From the sounds of it i really believe it is your catlytic, but im not an expert...good luck bud

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sounds like what happened to my impala.  started out like that and progressivly got worse until one day i could only do 60 on interstate and it had a hard time getting going at stop lights, ended up being the catlytic converter....went out on my impala at about 70k.  I would say take it to your dealer though, becuase if it is your catlytic, then you have emissions warranty until 80k and it would be covered under that.  They did all the work on mine for free.  Plus, since your check engine light came on, the dealer can hook it up to the puter and tell you what is wrong.  It will prolly cost you $40 or so to have them do that but once you find out what is wrong, you can decide what you want to do about it, fix it your self, have them fix it or take it somewhere else.

From the sounds of it i really believe it is your catlytic, but im not an expert...good luck bud

That's odd, my Catalytic Converter is crap, and my car accelerates fine

It's so old and worn out that parts have broken free and rattle all the time, This has been going on for over 2 years, since before the car was given to me. I hate the noise, but until the car fails inspection, I'm not waisting the money to fix it :P And it's been through 2 inspections that way, the last one was this past January :lol:

As for the rattling sound...well that's what the stereo is for ^_^

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That's odd, my Catalytic Converter is crap, and my car accelerates fine

It's so old and worn out that parts have broken free and rattle all the time, This has been going on for over 2 years, since before the car was given to me. I hate the noise, but until the car fails inspection, I'm not waisting the money to fix it :P And it's been through 2 inspections that way, the last one was this past January :lol:

As for the rattling sound...well that's what the stereo is for ^_^

o yeah...your catlytic can go out and do nothiing more except rattle around in there....its just in mine it got plugged by the stuff that was rattling round. The catlytic was out in my old suburban before i got rid of it but i didn't lose any power so what did i care. And if it woulda caused problems, I woulda just cut it out and welded in a pipe instead of dropping a few hundred. no inspections in ND

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is your 3800 Supercharged?

if so it may be your boost solenoid, I just had to change mine in Riviera as the car felt like it had no power and the service engine soon light came on...

But I believe there is something else wrong with my car now, as it still accelerates like $h!

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Well when you say it won't rev past 4000 rpm is this in park or neutral by any chance because i know some cars have a rev limiter in park and neutral just a thought. Also sometimes if your fuel pump may be going or the filter is clogged you will get some high rpm hesitation because it almost sounds like it isn't getting enough fuel especially at high rpms so I would for sure get that check engine soon light checked out because that might be a key to properly diagnose the problem... And don't be afraid to take it up to autozone you will save some money and normally they can help you out plus its free.

Edited by reeferman

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The airfilter is good. I'm going to run it by the dealership and have them tell me whats wrong with it and what my options are. If it ends up being something serious, I'm going to take it to the mechanic down the street. I'll follow up and let you know what it is. thanks!

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o yeah...your catlytic can go out and do nothiing more except rattle around in there....its just in mine it got plugged by the stuff that was rattling round.  The catlytic was out in my old suburban before i got rid of it but i didn't lose any power so what did i care.  And if it woulda caused problems, I woulda just cut it out and welded in a pipe instead of dropping a few hundred.  no inspections in ND

No inspections, lucky!

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It turns out that the Catalytic Converter had gone bad. They dealership replaced it under the 80k mile warranty under the special parts so it didn't cost me a dime

thanks y'all

Edited by turbomattk

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Yeah, too bad I came in a little late on the power curve with this one. I've driven a couple of cars with the cat bad on it and it acted just like that, but at the same time, you can have a catastrophic convertible (what a customer one time called it) go bad and have it just rattle.

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i had the same problem with a cat and the mechanic whose a friend explained the honeycomb layout of the cat. eventually it will just collapse and clog up the works.

now the bad part...when used too long it begins to glow red from all the trapped heat. drive too long like that and things could really get worse.

good thing you caught and took care of it. let it be a lesson.

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