Misfire on cylinder #1

I have a 2003 Chrysler Town & Country and the check engine light is on. I brought the van to my mechanic and he told me there was a code that told him there was a misfire on cylinder #1. He started out with replacing the wire to cylinder #1, no change. He replaced the spark plug, no change. He installed a new fuel injector, no change. The van runs a little ruff at idle and when at a stop light. We are both puzzled about this and he has run out of ideas. Any help would be greatly appreciated.


Have you checked compression?

Have you verified that the spark plug is firing?

Yes, he told me that the spark plug was firing. I don’t know if he did a compression check.

How many miles on the van? With the spark plug, or plugs, out a compression test should have been run just to make sure everything is fine with the engine internals.

Assuming the compression is good; some possibilities could be:
Faulty coil.
No power provided to the injector.
Problem with the ground circuit for the injector. (Ground is made through the ECM, or computer.)

With the engine idling he should hear the injector faintly clicking due to the ground circuit being open and closed inside of the ECM. If it is clicking then maybe the plug needs to come back out and at least check the compression on that particular cylinder.
If it is not clicking then he needs to check the injector electrical circuit. It’s not that difficult.

I would have checked the coil. An intake manifold leak can also cause this.

So would a burned valve.

have the code deleted and see if it happens again. In my experience using my hand held code reader is that 80 percent of the time they stay off which I think is due to water in fuel, corrosion breaking free in the injectors and such.


OP says the car is running rough

OP has a misfire code

Sounds to me like there is in fact a misfire

How would simply clearing the code help, other than extinguishing the MIL?

I suggested water in gas which can cause both the misfire and rough idle.

@shannondarst Thanks for explaining that to me.

So perhaps OP went to the “wrong” filling station and got a bad tank of gas?