I just went through changing the timing chains, phasers, tensioners, guides...etc in my 2006 Navigator 5.4L and I am having an issue.

Everything went fine with the install, she fired right up and all the noise is gone and otherwise running good. The issue is that under heavy acceleration I am getting some stumbles and rough running.

I have Dash Commander diagnostic software and I am not getting any misfires, fuel pressure is 39lbs or so I am not sure what else I should be looking at. Any thoughts?

thanks

mhburris

 

How many miles on the spark plugs?

 

I replaced those a year ago or so...maybe 15,000. I recently replaced the VCT solenoids too.

The only thing that I was 100% sure that I got back on the correct way were 2 little square black senors (one on top of each valve cover) with a single wire running to them. Not sure what they do.

 

Hi.

These? ==> https://www.f150online.com/forums/5069023-post4.html

MGD

 

Yep, that's them

 

Yes I would like to know what those things are as well :P

 

Did you read this part...
"I believe you are referring to the noise suppression capacitors which are bolted to the intake manifold. Should look something like this:"

 

Oh, of course not -_- My fault on that one :P, I just clicked and saw a picture and ignored everything else :P, thanks for pointing that out there.
But, if you don't mind telling me or attempting to, how do they suppress any noise what so ever, if that is what they are for atleast, or what is there purpose? Can they go bad?

 

They filter RF to keep your radio from being noisy. Sure, they can go bad, but other than radio noise, that won't affect anything.

 

Check your PCM wiring and make sure it is not in contact or resting on top of the air conditioner parts underneath the PCM. I learned that the wires can get interference from the A/C lines underneath them and create havoc electronically. Simple fix to zip tie the PCM wiring away from the A/C accumulator. Search it on the forum. JBrew on here is the teacher. My truck was misfiring and showing multiple "cop" codes when I knew the cops and plugs were ok.

 

Try cleaning the MAF.