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1993 dodge van problem

I have a 1993 dodge ram 15 passenger van. When it is cold, it runs fine, but after it warms up it starts to miss on the 6th cylinder. We have checked the plug and wires. Did not get anywhere. We replaced the injector. No dice. Any other ideas?

You need to do a compression check on the engine while it is warm.

When the engine is hot remove the distributor cap and try wiggling the rotor from side-to-side to check for a worn distributor shaft bushing.

I’ve seen this happen on other high mileage vehicles with distributors. As the distributor gets hot from the heat off the engine, this causes the distributor body and bushing to expand at a faster rate than the distributor shaft. This then causes the distributor shaft to wobble as it rotates. Then as the rotor comes around the gap between the rotor and the distributor cap becomes so great that either a weak spark or no spark is created for that spark plug wire causing the misfire.

Tester

thanks, gonna try that

Has the car been hooked up to an ignition analyser? That would quickly find the cause of any ignition problems like this. Might be worth it if you run out of ideas. I assume you know it is #6 because when you remove the #6 spark plug wire, it makes no difference, while all the others make it run worse, right?

It was diagnosed by a mechanic, they hooked it up to a computer.

Did the mechanic tell you that it had not spark on #6. If so, try replacing the distributor cap, it could have a hairline crack.

plug and plug wires have been replaced. I’ll look in to distributor cap.

@ozarkguy … you need to determine if the miss is caused by lack of a spark at the no. 6 spark plug – or something else, like lack of fuel at that cylinder, or lack of proper cylinder compression. Without knowing that, it’s a guessing game at best. Your mechanic who did the computer test should be able to tell you, one way or the other. Once you know, come back here and tell us what the mechanic says, and folks here I’m sure will try to help you out to find a sol’n. Best of luck.