I posted a few days ago about bucking and poor driveability in my GTA with TPI. I put new plugs in, which did not help at all. I tried it later, and with nothing else done to it except for sitting there for a half hour, the car started ! The car drives perfectly for a few minutes, plenty of power, then fades out, and dies. It will then restart, and will idle, but will die if you give it any gas.

This problem started out 5 days ago with the bucking, then the next day the car wouldn't fire up at all, although the engine turned over, now it fires up and runs perfectly for a few minutes, then will only idle. I changed the fuel filter 20,000 miles ago.

Thanks for any clues !!




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88 GTA Charcoal Grey Bone Stock except for loose muffler which makes it a bit louder than normal.

 

What about a bad computer ? Would that possibly let the car run OK in "non-computer" mode until it reaches operating temp, then go into "computer" mode (closed loop?) and die due to bad computer ? Or would a bad computer chip not even let the motor start ?

 

20,000 on a fuel filter is a lot of miles. Should replace it as a precautionary measure anyway.

You need to figure out if it's fuel or spark causing the problem.

Do you have a fuel pressure gauge? That's where I'd start.

Does the SES light come on when the engine is bucking?

Does the ECM set any codes? Have you looked at the cap and rotor and reluctor?

There's a host of things to look at that can give you some visual clues, others that can be tested with an inexpensive DVM, and some things that you need to spend a few more dollars on for the proper equipment.

 

20,000 on a fuel filter is a lot of miles. Should replace it as a
precautionary measure anyway.
You need to figure out if it's fuel or spark causing the problem.

Do you have a fuel pressure gauge? That's where I'd start.

Does the SES light come on when the engine is bucking?

>>> yes

Does the ECM set any codes? Have you looked at the cap and rotor and
reluctor?

>>> The ecm has a code 53 in it. I haven't looked at the cap, rotor, or reluctor, but my mech has and says it is OK. Interestingly, my Chilton's doesn't even list a code 53 for an 88 GTA, but they do have a code 53 for a 94 GTA. Maybe a previous owner put in a newer chip.

There's a host of things to look at that can give you some visual clues,
others that can be tested with an inexpensive DVM, and some things that
you need to spend a few more dollars on for the proper equipment.

>>> I decide to take it to my mech. He is going to take out the computer and check it out, look at the board for burned out spots. He thinks it is either the computer, a clogged cat, or the fuel pump acting up. He said he would have to drop the dash to get to the computer, but I thought it was right behind the kick panel on the passenger side.

 

Since the SES light is flashing at the same time the engine is bucking first I'd complete the tune up with new cap and rotor, this will give you the oppurtunity to look at the reluctor as well.

If the problem still persists, then replace the PU coil first (requires removing the distributor), it may be the ignition module as well, but when I've had the IM go bad, it would just go...no bucking etc...just dead.

When the SES light is flashing, the engine missing at the same time, what's being reported is that the key is on and no ignition pulses are being received..do change the fuel filer though.