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1989 cavalier idles fine somtimes. Dies/ backfires when you give it gas

I drive a 1989 chevy cavalier 2.0. A few days ago we couldnt get the car to start. I recently changes my spark plugs but not the wires due to them not being in stock. Once the car wouldnt start we disconnected the wires and reconnected them and the car would start and drive fine unless you mashed the gas from a sitting point. Now the car will start and idle a little high and shake the car(i have a broken motor mount somewhere) if giving gas at all it will backfire or die… Can someone help me figured out what might be happening

Addition the car only has 99,000 miles and it also missfires sometimes

Replacing the wires and having the motor mount fixed should be done first. The wires should not be hard to find. Any problems after that will be easier to solve.

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The wires will be done tonight once i can get a ride. Now im not very savy mechanically but from what ive seen from searching it could be an MAF issue however my car has a MAP instead is it possible that my MAP coukd be bad as well?

1999 Z24 am only owner still running great
if this helps, the ONLY problems I’ve had to correct

  1. original Chevy batteries replaced with MAXX
  2. sometimes contacts need cleaning to horn under steering pad
  3. power window motors - on set #3
  4. surging/dying corrected by cleaning throttle body + replacing I.A.C. Valve (all DIY possible)

Can you use a vacuum gage? The symptoms would suggest a vacuum leak.

Possible, but unlikely. I have a Corolla of similar vintage so our cars are probably configured similarly. EFI, conventional distributor, electronic ignition, right?

Your symptoms could be caused by a host of potential problems. Hard to say which one(s) are doing it via the internet. You might be able to fix it by guess what part is the problem and replacing it. But with EFI, you can quickly run out of money before you run out of guesses. What I’d do first if I had that problem on my Corolla is bring all the applicable routine engine maintenance up to date, engine air filter, spark plugs, spark plug wires, distributor cap, ignition rotor, valve clearance, vacuum system check, and read out any diagnostic codes from the computer memory.

If you feel really lucky, check to see if the brake power booster is leaking vacuum.

Old car like that could have a computer failure. If it were an 85, those symptoms would probably indicate that.

I’m glad to hear your car has been good to you :slight_smile:

That being said . . .

How do numbers 1 through 3 help the OP . . . ? :confused:

Firstly I would make sure the wires were on the correct plug. These things were notorious for failing crank sensors. It’s attached to the bottom of the ignition module under the coils. You can remove it and see if it’s cracked. You can also check resistance while it’s out. 800-1200 ohms is specs for that sensor. Of course, wires may be all you need.