srob

I have a 2006 F-150 with the 5.4L. The truck has developed a rough idle at idle. I notice it at a stop light as well as sitting in park. When the truck is in park I can rev the engine upwards of 3-4k rpm and still feel the roughness. It shakes just enough to where you can feel it in your seat or if you have a water bottle in the cup holder you can see it shaking the bottle. No code thrown at all, even ran it for ghost codes and nothing comes up. Sometimes its worse but there no rhyme or reason why.

Also had both cam phasers swapped, VCT solenoids, COPs, I had plugs swapped with SP515, all back in January. This started about two months ago and has gotten worse over time. I changed the basic items about the time it started, fuel filter, air filter, cleaned MAF, TB looked good.

I took it to a shop and they said they could see 5 & 6 misfiring when they hooked it up to the computer. I swapped out those two COPs with no change.

Any ideas? My next thing is to change out COPs on 1 & 2 in case it was misread on the computer. Plugs should be fine given that I have barely put 4k miles on it since January.

Baja Kits

PCV Valve?

techrep

iTrader: (1)

We don't have PVC .. Serviceable anyways

nrivera04

Try changing the 2 plugs out also for sh**s and giggles... Sometimes an issue presents down the road after a plug change.

Deathtofishy

I'm a bit confused if you're trying to fix things or a shop has been or a little of both... But here is where I would start.



1. Maybe time for a new shop. Especially if they have been making repairs this whole time.

2. Agree with prior post, just cause plugs are new doesn't mean they can't be faulty. Try new ones, cheap and easy to swap.

3. Has your PCM been flashed to the latest firmware? There is a rough idle TSB out there on the 5.4 if I remember right. But either way it's a good idea to have it flashed, also the tech should erase any "learned" adjustments the PCM is currently making. You'll probably have to go to a dealer for this service.

Summers22

iTrader: (2)

Also what brand of COPs were used?

Deathtofishy, please show me a picture of a PCV for our 5.4's

Deathtofishy

Sorry post edited. My repair manual specifies that it has one just like the 4.6. But in searching online it appears to not be the same.

Summers22

iTrader: (2)

Thank you for that. Yes, the 4.6 does have one on the 11th gens. Some people confuse the tube assembly on the driver side valve cover with a PCV as well.

I am curious as to what COP brand was used.

Also to the OP, have you inspected your FPDM on the rear cross member by your spare tire? If it has been raining in GA, that could be the issue. Drop the spare and inspect the entire unit. Here is a link: https://www.f150forum.com/f4/fuel-pu...-yours-152908/

srob

1. I've been doing all my own work so far besides the buddy that helps every now and then and I use a local shop to help me diagnose problems I can't. The only item replaced since the rough idle showed up are the two COPs on 5 & 6. All the other items (cam phasers, vct solenoids etc) was done due to the fact I had the infamous diesel sound. Found out I had bad tensioners when I got into it. Figured since I was in there I might as well put in new parts as I reassembled everything.

2. I swapped plugs today and no change.

3. I have not tried this, nor heard of it. Definitely something I'll look into, I'm starting to run out of options as it is right now so it might be going to dealership anyway.

srob

I use the COP that I've heard several guys on here use from Global Automotive off eBay. I put a set of the COPs on the truck right after I got it 2 years ago and they've been flawless so far.

I did check the FPDM today, it looked a little corroded but nothing major. I cleaned it and put it back. If nothing else works I may swap it out for the heck of it.