CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Chevy venture misfires

I have a 2000 chevy venture with 139,000 miles. In the last year I have had one problem after the other with it. It all began when I ran into a snow bank one icy morning, minor damage to my bumper. Then a few days later I started hearing a whining noise from the engine , thought it was a belt, so my husband sprayed it with something, didnt help. Well, I took it to auto zone and they said it was the harmonic balancer. So we replaced it, problem fixed. It drove perfect, until I drove over a large curb at the auto store returning a part. Then as I was leaving the store my car started bucking, and continued to buck off and on till I got home. It did this a few times every day. I took it to auto zone again and had it hooked up to their scanner. It came back with “multi cylinder misfire” and “crankshaft position sensor”. We replaced the crankshaft sensor. Then it ran worse! I finally broke down and took it to a mechanic. He said it needed a complete tuneup and new coils at a price of around $600. We decided to fix it ourselve and changed spark plugs, wires, oil and filter, fuel filter, but not the coils. Anyone have any ideas? Could it be the coils, or maybe need the injectors cleaned? Could running over the curb have knocked something loose? Also, my check engine light has been off and on off and on, now its off.

Also, my check engine light has been off and on off and on, now its off.

Stop by the auto parts store and ask if they can read the codes for you, some will do it for free. You may be able to extract codes even after the light has gone off. Post the exact code back here (code format [P0123] Lets see what the computer thought was a problem before we all start guessing.

The first time I had the codes checked it was PO300 - cylinder misfire and PO336 - crankshaft position sensor. Then we changed spark plugs, etc. and the codes were gone. Then check engine lite was on again so I took it back and codes were PO336- crankshaft, but we already changed the crankshaft sensor on the front. Could be the back one but I was told if it was bad it wouldnt even start. Thankyou.

The curb may have damaged the exhaust (catalytic converter), and it may have broken the oxygen sensor, and damaged some wires.
Run the van upon ramps (etc.), get down and under, and closely examine those parts.