Ok. Here is the deal. This started a couple months ago, when we start the suburban cold, it runs real rough at anything between idle and about 2k RPM. Does this until it fully warms up to temp, and still fishbytes some afterwards.

I have been chasing around the usual things, checking lift pump pressure etc. We had the IP replaced at the stealer under warranty about 3k miles ago.

Unless it has run for a few minutes, you are lucky it will even move. It does idle perfectly though :-) it acts like there is air in the lines, or running out of fuel (which I have checked for of course)

Symptoms are similar to http://www.dieselplace.com/forum/showthread.php?t=232607&highlight=P1217

Yestarday/this morning I had a chance to check for codes again...

P0228
P1217
U1026

I know what the different codes mean, and from my research, a 1217 indicates I probably should get it back into the dealer?

We are getting close to the end of warranty (like 116.5k miles right now)

I need to $%#% ($@#%) or get off the pot here, but the last time I took it in, they said they were gonna charge me for diagnosis if it wasnt the pump/pmd.

I do have a spare 'unknown' PMD, but I currently dont have any place to mount it. How 'bad' would it be to just plug it in, not mounted for a few minutes, just long enough to do a cold start, and see if the problem goes away?