DeJay561

Working on a customers 2006 Ford F-150 over 120k, complaints were rough idle power hesitation when accelerating and misfiring. I've already replaced the spark plugs, coils, fuel injectors and even the valve over gasket (due to oil leaks) and still having issues with rough idle. The catalytic converter does have any rattling but I removed it and looking to replace it but before I have the customer come out of pocket wanted to see if anyone has any recommendations and or suggestions on anything else I should look at. Home mechanic with limited resources. Any help is appreciated.

Thank you

needsmoarturbo

Which engine?
If 5.4 could be phaser/timing issues.
Have you looked at the FPDM on the rear frame cross member. They can cause all kinds of issues if corrosion has taken over

DeJay561

Yes it's the 5.4. and no I never even thought to look at that. My background is with Toyotas so Fords are new ground for me. I'll check it out. Would there be a particular code for it or would I be able to see any drop in voltage on a live graph for this if its the culprit?

needsmoarturbo

For the fuel pump you can monitor fuel pressure and see if it drops out or fluctuates and coincides with the rough running.

The phasers are a whole different mess it's hard to tell you where to start there, but a lot of it comes down to oil pressure. Typically phaser issues might show up as normal running for the first 10 minutes,. It then gets rough when the oil is warm and pressure drops.

DeJay561

Awesome, hopefully the fuel pump and or FPDM will the issue, but if not at lease I'll know where to go next. Thank you for the direction really appreciate it.