90 vette wont accelerate
Thread Starter
4th Gear
Joined: Oct 2007
Posts: 4
Likes: 0
90 vette wont accelerate
I am having a problem with my 90 vette. its all stock. The car wont accelerate above 3,000 rpm then it gets all slugish like its not getting enough fuel. I replaced the fuel pump and I still have the problem. The car doe idle roughle. its stable rpms but jumbles occasionally. And when I try giving it alot of gas to drive through it possible i have recently hear what sounds like a bang from the engine, not backfire though. it doesnt bang often, just when I floor it. I can still drive it at low speed and low rpms. any suggestions?
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Possibly clogged cats, but I would check the fuel pressure as well.
Assuming there are no codes and that it does it at all times.
Assuming there are no codes and that it does it at all times.
Thread Starter
4th Gear
Joined: Oct 2007
Posts: 4
Likes: 0
The problem got progressively worse. When it started happening my engine would die when I slowed down, and then it would start up once or twice and drive for 3 more minutes then die again adn then it wouldnt start again. it would crank but not turn over. I also replaced the alternator a month ago
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Le Mans Master
Joined: Jan 2008
Posts: 7,030
Likes: 10
From: Edmonton, Alberta
Have you ohmed your injectors?, My 90 had some of the same symptoms as yours. You said it was all stock so that means you're running the Multech injectors. It might be time to change them
Jim
Jim
Racer
Joined: Oct 2001
Posts: 311
Likes: 2
From: Roseburg OR
do a search for multec injectors
My 90 was stock with 108,000, tuned it up when I got it and later it started to lose power and here is what I did.
Tune-up consisted of; plugs, wires, cap, rotor, ignition coil (they do wear out).
Then it slowly started to run bad and the driver's side cat started to glow red. Replaced injectors and put a Flowmaster Force 2 for the LT1 on (no cats). When I took the cats off, the smaller ones were breaking apart and clogging the main cat.
Brought back power I did not have before. If you have the stock injectors that would be the first thing to replace. Don't be cheap, just replace them, will save you a lot of time.
I'd also stay away from the using an exhaust with an Y-pipe, I think it contributes to resonance.
Tune-up consisted of; plugs, wires, cap, rotor, ignition coil (they do wear out).
Then it slowly started to run bad and the driver's side cat started to glow red. Replaced injectors and put a Flowmaster Force 2 for the LT1 on (no cats). When I took the cats off, the smaller ones were breaking apart and clogging the main cat.
Brought back power I did not have before. If you have the stock injectors that would be the first thing to replace. Don't be cheap, just replace them, will save you a lot of time.
I'd also stay away from the using an exhaust with an Y-pipe, I think it contributes to resonance.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
And another vote for bad fuel injectors here.
Not to say that your cats aren't failing or clogged but usually they don't cause the car to stall out unless they are totally stopped up. Blocked cats do cause a lack of power, slowed engine RPM response and the engine may run at a higher temperature....once the exaust is hot the blockage may be more obvious....so keep an eye on that coolant gage.
Good Luck!
Not to say that your cats aren't failing or clogged but usually they don't cause the car to stall out unless they are totally stopped up. Blocked cats do cause a lack of power, slowed engine RPM response and the engine may run at a higher temperature....once the exaust is hot the blockage may be more obvious....so keep an eye on that coolant gage.
Good Luck!
