We have an 02, 4.7 liter that has had horrible diagnostics from the local Dodge house.

The truck has, believe it or not, 50k miles. Never any major mechanical problem. One day it began running very rough, as if it wasn't firing on all cylinders or had bad gas, etc, and eventually died when the engine began to warm up. The only light to come on was 'check engine'. We didn't run the sequence to see the OB? codes.

The local Dodge dealership diagnosed a huge laundry list including fuel pump, catalytic converter, 02 censors, cam sensor, battery, and a few other things.

They changed the catalytic and put a battery in. Spark plugs were changed at the first mechanic it went to prior to the dealership.

We put 02 censors, cam sensor, and changed the fuel pump. No change in running condition.

Come to find out we got an old school mechanic out that found five of the eight coils were bad. (a series of checks he did including firing and resistance).

My question is: What in the hell will make five of eight go out? How did this not easily turn up on the dealerships list? When we replace the five tomorrow night is there another problem within the truck that will make the new ones go bad as well? Has anyone else run into this situation?

I have included all the information I have as to the nature and what has been done already.

Thank you very much.

 

Well, it he had only done a test for fire I would say the computer was the problem. But since he checked ohms as well.......
I'm lost.
Do they not fire at all or just not all the time?
Your'e running on 3 cylinders?

 

sounds like you had a voltage spike that killed the coils, and all the other items. I'm amazed the computer is still alive.

normaly coil are pretty stout, but shoot them with more than 15-20 volts and the voltage increase will burn out the windings.

 

Thanks guys. We changed the coils and everything is working fine now.

Any idea what would cause a voltage spike? We're also not sure the parts previously replaced were actually bad.

Thanks again.