EcoFX4d

Did a data log from the driveway all the way in to work. I had one decently significant shudder for about 12 seconds after driving for about 30 minutes at a steady 65-70MPH. The first attachment is short term A/F ratio. If I'm reading this right, you can see bank 1 (yellow) goes rich at the same time frame of climbing the hill, (which also corresponds to the throttle plate wigging out at ~1988 seconds), while bank 2 stays lean as if we were still just cruising and then catches up as soon as the waste gate settles down. A/F ratios are pretty well in line with each other at just prior and just after the event.

The second attachment is throttle position of the pedal (blue) vs the throttle body (purple) in itself in percent. It seems that the graph has a consistent 5-6% difference between the two except for when the shuddering occurred (I highlighted the start of climbing the hill). You can see the throttle plate snapping open an additional 5% three times during the climb. The orange line is wastegate opperation in percent. You can see that the truck started dumping boost significantly after the second spike of the throttle plate.

Does this all make sense to anyone else?

Centexguy

The a/f explains why it seems to damage the driver side cat.

Interesting note concerning this, whenever I would run stock or my 87/93 performance tunes I would receive a cat converter efficiency code after about 50 miles. I ran my 87 economy tune and put 600 miles on it with no light. Dealer only replaced my driver side cat.

EcoFX4d

Oh yah, forgot to mention that I removed my SCT 87 tune. This is back to stock form. I plan on driving it for a couple weeks stock before I go to the dealer to try to get the ball rolling on the latest TSB.

Centexguy

If your cel is on it should be an easy diagnosis. At least it was for me. They had the truck an hour and had everything ordered already.

EcoFX4d

Since day 1, I have NEVER been able to get the CEL to light or flash... But I don't have the fall on its face issue either.

Centexguy

Weird. Mine fell on its face twice before it threw a light and then it never went off.

B1gfun

Having this issue now. Seems to be when I kick it down to pass it happens. Anybody have the TSB # for this?

maplelakeduckslayer

Look at the condensation thread at the top of this sub section.



Mine has fallen on its face twice and does the miss/shudder when adding a load to the engine(uphill, slow acceleration, etc) and has never thrown a code either. The miss/shudder is east to replicate, the complete loss of power not so much.