Hi,

I have a 2006 F-150 FX4 5.4L with 100 000 KM. The truck has a PHP gryphon with custom tune, LT headers, Magnaflow hi-flow cats, true dual and Gotts mod. The truck has been experiencing some shudder. It basically can show up anytime while under load, at idle, while accelerating and once it starts it will not stop unless I shut down the truck at start it back up.

I have heard about the transmission problem causing shudder but the shudder keeps on going even while in park so I doubt that the transmission is the problem. You can correct me if I'm wrong.

Any idea where it can come from?

Thanks,
Pat

 

Does it still do it if you return the tune to stock?

At that mileage, you should probably change the spark plugs and get a transmission fluid exchange.

 

1) Add Lucas Oil restoring stuff for transmission.
2) Add restore oil to the rear differential.
3) Change spark plugs.

I would try these things before digging too deep. Spark plugs can be had for 80 - 100 bucks.

Mine and my brothers truck (both 06 XLT 5.4) had a shutter or vibration under load. It was the rear differential needing oil. We used the restoring kind (forgot the exact name or term) and it went away.

We both also had COP problems that would cause a stutter. It was it slightly miss firing.

I had a far worse problem that was a spark plug going out. It never threw a code and it only went away when I changed them all.

 

Spark plugs are new (4,000 KM) had the a Ford dealer change them with OEM motorcrafts. The shudder was already there before changing the spark plugs. I have a set of brand new Visteon COP waiting in my garage to be put in. Both differentials have brand new oil with friction modifier from last summer when I had 4.56 gears put in. But I doubt that the shutter comes from the diffs or tranny since it keeps vibrating while the vehicule is in the park position.

 

And yes GLC the vibration still shows up from time to time when the tune is returned back to stock.

 

I'd clean the throttle body and MAF.

 

Sorry, I read over that in OP.