Well on the Suggestion of 98whitelighting, i lurked around searching on here for what my issues may be but to no avail i didn't find a solution to my problem. As of 2 days ago my truck was running just fine, then my CEL came on i went to parts store scanned and came back with P0237 MAP truck ran fine though so i cleared, came back about 6 hrs later cleared again probably coming on because of my XZt+ i had just uploaded a new tune to it. I don't know if this coincides with my issues from today, truck was driving fine this morning went to pick up a load for our job site and on the way back cruising about 35MPH truck just shut off, I checked fuel canister had bout half canister i topped it off, had plenty of fuel in the tank. tried cranking for about 5 mins to no avail so i had it towed. As to that point i searched all over Cumminsforum with no luck to my issues, so i figured id try over here. i have unplugged the XZT+ checked Batts, unplugged APPS and reset tried jumping the MAP Could a bad MAP cause a no start? i dont have the socket to take it out at the moment to clean. i can hear my LP buzz for bout 2 Secs when key is turned on no start like normal. Only conclusion and can come up with is maybe my VP is shot? ive checked fuses/relays all connections still just turns over. And i haven't installed a FPG yet i know thats a first for these trucks i just havent had time with work very busy lately. I'm sorry for such a long post im just trying to cover every issue that has happened and step ive taken to resolve. Any help or input would be greatly appreciated. Thanks

Well since this i got it going, Have since sold the XZT been running it stock. Now i think my VP has ate it...

Sounds like the XLT is giving you the code. Internally screwed up on the boost fooling circuit. As for the battery voltage you look like you got some rotten cables if the voltage is wandering that wide from one side to the other. Might consider this test... http://articles.mopar1973man.com/general-cummins/34-engine-system/136-voltage-drop-testing-of-wiring-and-feed-cables As for ether don't use it... Your taking a risk of the grid heater possibly igniting it in the manifold and cause a explosion. If you need to use it make sure to unhook the grid heater lead from the battery so the grid heater will not come on.

Along with the pssibility of the grid heaters igniting the ether, it has a nasty habit of cracking piston rings. Just recently had to overhaul 3 engines from them being started with ether. Each engine had a minimum of 2 cylinders where the upper compression ring was in 3-4 pieces.