Please help with my '98 Sunfire

I have never had a serious problem with my car and now I can't even pay someone to fix it. When I accelerate it is really rough and at times bucks and shakes. If I push on the gas lightly the problem will only come when I get to a higher speed. Even on the highway with cruise control on. I've had a tune-up and replaced all parts and still no help. The mechanic even paid $250 to the dealership for a diagnostic and still no help. If anyone has had this problem with the car riding really rough, please help

go get some carburator/choke cleaner, pull the plastic intake tube off of the throttle body, now by hand open the throttle plate and clean the throttle plate and the bore really well. dont' worry about the fluid getting into your engine, it'll burn off. now with the intake tube still off, start your motor. it may run rough, but it will run. now spray the carb/choke cleaner into the throttle (don't open it this time, or the engine will die) in short bursts. the engine will try to die, but it won't if you don't spray to much in at once. now turn the motor off, and put everything back together. if this doesn't take care of your problem, then get some CRC mass airflow meter cleaner and follow the directions on it. if this still doesn't fix it, then I couldn't tell you what was wrong with it without physically seeing it.

I have never had a serious problem with my car and now I can't even pay someone to fix it. When I accelerate it is really rough and at times bucks and shakes. If I push on the gas lightly the problem will only come when I get to a higher speed. Even on the highway with cruise control on. I've had a tune-up and replaced all parts and still no help. The mechanic even paid $250 to the dealership for a diagnostic and still no help. If anyone has had this problem with the car riding really rough, please help


Welcome on your first post on AF.
Without looking at it or some proper testing is the only to see what is wrong.
Any check engine lights on?
How is the fuel pressure?
What kind of plugs did they feed it.
Lot of problem with the coil cover and coils on some of them.
What engine?
Try what rsxse240 said.
If that does not help I would suggest looking for a good mechanic or dealer.
I would ask for my money back on that 250 dollar dealer diagnostic.
Tip on going to the dealer
Ask that only a factory certified gasoline engine performance specialist work on your car.
Not all dealerships are concerned with how repairs are dispatched, and not all dealership techs bother to take advantage of the training offered by factory (the vast majority of which is paid training). If the dealer is uncooperative, ask for your money back and call around for a dealer that will accommodate you.

Or just check around for a good repair shop.
Check around Ask around
Word of mouth.
Family friends coworkers neighbors business people and delivery people.
Mailmen and parcel delivery people get around and notice a lot of stuff.
Even a good parts house knows what shops are good and not good.
Chamber of commerce and better business bureau and city hall.
If you find a good referral to a repair shop go look them over and talk to them.
Look for a clean looking busy place with nice people running it.
Ask a few questions and ask about their qualifications and training.
Not all places have trained tech/mechanics.
If they do not find a place that does.
Even all dealers do not have all trained techs/mechanics.

Let us know how it goes.
MT

I've had a mechanic working on it and I will definately have him try what rsxse240 said to do. It couldn't hurt. As for the dealer that was a joke. Luckily I didn't have to pay for it the auto shop did. The engine is a 4 cyl. 2.2L. Great car that now has a mystery that no one can solve and I can't afford to keep having people try.

I've had a mechanic working on it and I will definately have him try what rsxse240 said to do. It couldn't hurt. As for the dealer that was a joke. Luckily I didn't have to pay for it the auto shop did. The engine is a 4 cyl. 2.2L. Great car that now has a mystery that no one can solve and I can't afford to keep having people try.


10-4 on that.
I would suspect something on primary ign.
Weak coil or ign cover or could have been a bad new spark plug.
What brand of plugs was used with tune up?
It needs some proper testing with a engine capable scanner.
Usually a good scanner will point to the problem.
It may show missfire or even what cylinder it is missing on.
Any check engine lights on?
Has the fuel pressure been tested?