What you explain is exactly what happens due to the intercooler. Check engine can flash shutting it into limp mode due to the misfires.

 

Yes, on this visit they could only find "1 misfire on Mode 6. Inspected the harness connectors, road tested 23 miles and couldn't duplicate. Has had all the newer TSB and updates already performed, no repairs made."

 

I'm headed out of town again tomorrow and I can bet good money this will happen again on this trip. This is pretty frustrating when it happened twice on a recent trip and it doesn't pop up on any diagnostic. I'm told I need to take it in before I shut the vehicle off so it remains on the computer but I usually travel late because of the Texas heat and that's not possible.

 

Have you changed your plugs and the boots on your coils.

The plugs in these trucks suck and get carbon arced and pockets on the tangs.

They should be replaced every 25K-30K.

 

I'm almost certain they did a tune up when they swapped the cat converter

 

I wouldn't count on it. Most dealers will only replace one plug at a time if that cylinder shows a misfire. thus is because the maintenance schedule shows 100k for plugs which is bull****.

 

Did you guys see the thread on the member installing a raptor transmission mount? It cured his vibration issues..

 

Update... Did not fix my issue. After a few hundred miles its doing the same thing again. Its either an out of balance driveshaft or my tires out of balance. Ive changed everything else.

 

 

I wanted to share my experience with the vibration/ bed shaking issue.

My recently wrecked 2006 F150xl 4.2l 2wd bone stock, would shake like crazy. The vibration was present at any speed but most notably between 47-57 and 67-77. Deceleration and braking was sometimes scary, especially when towing.

I believe this defect contributed to the loss of traction and subsequent crash while I was traveling about 55mph on wet pavement (no rain). As the weight shifted from left to right into a left-handed, slightly uphill bend, the rear-end wonder into the right lane until I was perpendicular to the guardrail. I was driving the same speed as surrounding traffic and my tires were in good condition. I have driven RWD trucks and cars my entire life and never experienced a rear-end slide so suddenly in either rain or snow that was not precipitated by acceleration. I was going steadily at speed in my lane.

Anyway, last year, 2014 I purchased a 2012xl 5.0 2wd stock. And I have the same bouncing/ shaking vibrations as my '06.

2006 was a regular cab with 1-piece drive shaft,
2012 is a super cab with the 2-piece drive shaft.

The vibration is more pronounced while towing my 1600lb trailer with either truck. Whats interesting is that whenever I'd load the tongue or weight the bed, the vibration speeds dropped from the normal range of 47-57, down to 40-50 instead.

When buying my '12, I complained of a pulsation in the brakes and a vibration when braking. My test drive area only allowed me to run it up to 45mph. Later the dealer resurfaced the rotors but that did not fix the problem. I simply excuse this as tire balance or road conditions at that time, naively believing there was no way the poorly engineered spirit of my recently totaled '06 was somehow haunting my newly redesigned '12!

It took me a year of ownership and several tire/ oil change mechanics reminding me of the "dude your truck shakes, are you aware" meme to finally accept the fact that my beloved '12 indeed came equipped with free massaging chairs. As do the newly redesigned 2015's?, sorry guys!

One final note. Some of you by now may have noticed that the vibration is cyclical. So at its most pronounced effects, at speeds of say 55 or 75 the vibration presents in equally timed intervals. For example, at 55mph the truck shakes or bounces etc, every 8-10 seconds and then smooths out for 8-10 more. And at 75mph as the speed of the vibration increases so does the length of the intervals to about 20 seconds long and then smooth for 10-20. However when the truck vibrates for 20 seconds at 75 mph it just feels like its vibrating all the time.

Has anyone ever tested on a dyno? I imagine that would be irrefutable evidence of how subtle or severe the condition?