3406E misfire that won't go away, even after overhaul

I had a 1998 FLD that developed a bozo misfire or jerking upon acceleration. It was not loping like a hotrod though. Turned out to be the pickup tube in the passenger side fuel tank was cracked. It was cracked up around the fitting. We just vice gripped the lines running from the tank until we found a used tank. You say it is specific to cyl 3. I agree with previous posts from the more knowledgable folk on here. Yet, if you haven't already done so, watch it run with the valve covers off. If you did not run the rack yourself, perhaps that rocker on 3 has issues. After you mic the cam, swap cam sensors etc, and if problem persists, and you trust the harnesses, I would move that injector on 3 to hole 1 or 5 and see if the CAT ET signal follows it. If it doesn't, bring it back and pin the motor in order to verify for certain for sure for sure for certain the engine is timed correctly. Just my wobbly 2 cents.

 

Move that injector on 3 to hole 1 or 5 and see if the CAT ET signal follows. Makes sense to me!!!!

 

You have to pull the head to put a new cam in an E model right? As far as I know mines original with 1.7 million on it, looked pretty good when I had the rebuild done.

 

I fought with this issue for 2 years after my inframe was done, turned out to be improperly machined injector seats on the reman head they put on. new head and injectors under warranty solved my miss.

Truck309 chased his miss for a couple years and tens of thousands of dollars and turned out to be a disintegrating fuel line.

 

That's why I would've changed out the cam when the overhaul was done what's another thousand or so bucks at this point!!!

 

Mine looked fine yet, runs good too, it'll be fine until I need an upgrade. I was running out of disposable cash to throw at parts at that point so I got cheap.

 

As long as it works Right.

 

If the lobe checks out fine, check the pins for injector 3 from the ECM all thru the leads running up to injector. Somewhere along harness leads you may be losing voltage. Though, even if voltage looks good, some harnesses act funny directly out of the package. Run some external leads from the ECM to the injector #3 with harness still connected and see if it energizes that cylinder on the CAT ET. You already ruled out ECM and fuel. If you pull the center valve cover and run it you could see if #3 is running or has a flat lobe.

 

I have pulled them on 379 Pete's and W9's by pulling the radiator. And leaning the hood forward.