Hi

My sisters 1999 Dodge Grand Caravan had a really bad backfire problem for about a month that was being caused by a spark plug wire boot coming loose on plug #3, the plug and wire needed replacing. Well I replaced the plugs and wires and got rid of the backfiring problem, but now the engine is running roughly and I can not for the life of me figure out why! I did a parcel Power Balance Test, I could not get to the injectors and boots for cylinders 1, 3, & 5 while the engine was running so I could only do half a Power Balance Test. But from what I was able to do, I found that there was some sort of problem with cylinder 6, when I disconnected the connector for cylinder 6 fuel injector there was absolutely no change in engine performance, and when I pulled the boot off of cylinder 6 spark plug there was only the slightest change in performance, compared to cylinders 2, and 4 which did change the performance of the engine. Another thing when I pulled the wires off of spark plugs 2 and 4 there where lots of BIG sparks coming out of the end of the wire, but cylinder 6 had no sparks coming out of the wire, I did put a spark plug in it to see if the wire was bad but it turned out to be good but the sparks seems to be weak. I still have to do a compression test and after that I don't know what else to try. I also had the battery and alternator checked but they are OK too. I'm running out of salutations on how to fix this problem, anyone have any salutations that might work?

 

Hi

I am getting two codes, P0351, and P0305.

 

Hi

I have a question, the original problem was a continuous backfiring, when I checked it out I found that the wire on cylinder #3 had disconnected from the spark plug. Could something like that cause the coil to go bad?

 

Hi

Well it turns out the new codes where because the #5 spark plug was bad to begin with.