89 Pontiac Bonneville

[rseragojr]

While driving,regardless of speed,the engine appears to be misfiring. The car shakes excessively and at times shuts off, it may take 4 or 5 tries to get it restarted. Our mechanic has tried desperatly to locate the problem but to no avail. All the spark plug wires were changed, tuneup, ignition coil, cam sensor, O2 sensor, fuel filter, pcv valve and air filter. The problem still exists. Its intermittant which complictes the issue so he has never been able to duplicate it at the shop, there has been times when he has had it for a week. Do you have any suggestions? Thanks

[FieroSpeeder]

is it a v6? 2.8 or 3.1

get a timing light and see if all the wires are emitting a light.

if some are not firing your ign module might be bad, if its the 2.8. they are around 100 bucks.

[rseragojr]

The motor is a 2.8 V6. It has 62,500 original miles. The ignition coil has been changed because of weak spark. this problem is intermittent. thanks for your reply

[kurtdaniel]

While driving,regardless of speed,the engine appears to be misfiring. The car shakes excessively and at times shuts off, it may take 4 or 5 tries to get it restarted. Our mechanic has tried desperatly to locate the pontiac parts (http://www.thepartsbin.com/guides/pontiac.html) that has to be changed. All the spark plug wires were changed, tuneup, ignition coil, cam sensor, O2 sensor, fuel filter, pcv valve and air filter. The problem still exists. Its intermittant which complictes the issue so he has never been able to duplicate it at the shop, there has been times when he has had it for a week. Do you have any suggestions? Thanks
I have similar issues with my 99 pont. I have changed plugs, wires, o2, tbs, and even went as far as replacing valve seals in the motor. It runs ok

[dougbfresh]

EGR sticking most likely-you need to pull the OBD codes when it happens.