Pontiac Repair: Backfireing, spark plug wires, cam shaft

Question
QUESTION: I have a 1994 3.1 Transport. When I accelerate or go up a hill it begins to jerk and backfire.  Thanks for any help you can give

ANSWER: Hi there:

I would have to say I would look at 2 things. The ignition system a bad distributor cap and rotor or a bad set of spark plug wires. The other thing to look at a plugged resticted fuel filter. that is not going to make it back fire but it can lack power. one other thihn that is distributor related could be a pick up coil in the distributor being bad. but that will cause a stall condition as well. good luck :)


---------- FOLLOW-UP ----------

QUESTION: Todd, I now have new spark plugs, wires, rotor, and distributor cap but it is still backfiring when you accelerate, but it only does it after the car begins to warm up. When I first take off and the engine is still cold it doesn't do it. The car is 17 years old would a warn cam shaft do this?

Answer
I highly doubt it. I would still be looking at a distributor/spark issue. Like I mentioned before the pick up coils in the distributors act up and cause all kinds of issues. to repace that you need to remove the distributor and then replace the coil then when it's put back in the engine needs to be times peoperly. did you look at a fuel filer? when the engine is cold it runs richer and it's easier for the fuel to ignite when it gets hotter it's leaner and leaner makes it harder for the ignition system to ignite the fuel so if there is an issue with the ignition system it can cause a back fire. coils on these things would tend to go bad as well. I don't wnat you to just keep throwing parts at this guessing it gets expemsive and getting it looked at by someone who knows what to look for may be cheaper in the long run then just tossing parts on this in hopes it's going to fix it. also in the distributor the timer cores would go bad on the main shaft the magnet would bloat out from the heat cycles and then crack the core on the shaft and the timing would be then "off". that is rare But I have seen that happen a few times... good luck :)