Ok, so we changed the battery cables and battery. Engine starts better now. But the running rough engine still exists. Changed the coolant temperature sensor. Changed the fuel pump and fuel pressure regulator. Tested both coil packs. Checked all the spark plug wires and spark plugs. Did a compression test. All cylinders 125-135psi. Changed the passenger side O2 sensor. None of which has changed the way this truck runs!

Anyone know how to check timing chain slack with this distributorless ignition? I guess injectors and the crank position sensor are the next things to check?

 

Refresh my memory, is this a problem that came on suddenly, or started small, and slowly got worse?

 

It started overnight!

 

Getting any codes?

Might try doing a power-balance test.

Start engine, let it idle, and settle to base idle. Disconnect IAC motor.
Disable one injector at a time. Just unplug it. If the cylinder is good, RPM should drop some.
See which cylinders are working, and which aren't. Compare that to which cylinders on on which coil pack. (individual coil packs, each one is responsible for two cylinders. the modules themselves deal with 4, or 6 cylinders.)
Any correlation there?

 

We plugged the computer into it today after we did the compression test and it said everything was fine?
My mechanic said we need to test the timing chain and see how far it's stretched after 214000 miles?

 

How does one start the engine and then just unplug the injectors one at a time? I can only get to, maybe, two of the injectors of the fuel rail. The intake manifold covers most of the passenger side injector caps and the air intake hose covers the driver's side injector caps?

 

This is where a scanner would come in handy..... but, barring that.... just pull the plug wire.

 

My mechanic has a bag of tricks like all the rest of my gear head buddies out there! He even called his dodge buddy today and we stumped him too! He said fuel pump or plugged cats! We know that's not the issue!

 

Problem is, the 8.0 is REAL reluctant to set misfire codes..... It runs too smooth, that I don't think it even notices a cylinder misfiring..... I had a dead miss on one cylinder, the plug wire was burnt in half..... and it never set a code..... I think I drove it like that for about a month.....

Do you have a scanner that can look at pending codes, or misfire counters??

If not, try the test, see what you come up with.

 

I don't have too many tools. But my mechanic has been in business a long time. He has the scanner and all those other specialty tools. I told him all that you told me up until what we have discussed today. He told me to do some more research. So I will take your knowledge to him tomorrow and see what we come up with! Thank you so much for the assistance!