I have a 96 F-250 with stage 1 injectors, adrenaline hpop, DP tuner chip, it runs great for about 15 min then when it is under a load in drive and overdrive two of the injectors quit firing and starts shuddering real bad. I have changed the UVCH and gaskets on both sides, put my original black CPS back in, changed out the IPR with another one i had, put new o-rings on it the electrical part of it is original though. I changed out the IDM with my Dads that did not help. Then I unhooked the chip, and it still seems to do the same thing just cannot tell as much with the lower horsepower but it still shudders at WOT. I'm about to give up! Any help would be great. OH yea the oil only has around a 1000mi on it Schaeffers 15-40.

 

Typically associated with worn injectors. Although you stated they are new?

 

They have less than 30,000 miles on them. I sent the two that was missing back to Full Force to have them fixed and they said there was nothing wrong with them.

 

How is compression in those 2 cylinders. Do u have any raw fuel out the tailpipe

 

They have less than 30,000 miles on them. I sent the two that was missing back to Full Force to have them fixed and they said there was nothing wrong with them.

 

I haven't checked the compression, and there is no raw fuel coming out of the tailpipe.

 

Have you tried unplugging the map sensor and ICP? Not both at the same time though.

 

have you ohm'd out the injector wiring and IDM when hot? if it truly is a miss and is not firing at all on certain cylinders when hot, it could be an intermittent wiring problem that only opens up/shorts when up to temp. there is a good write-up somewhere on the web for testing the wiring from the IDM to the injectors before replacing your IDM. i think it is from a company that remans IDM's. i'll poke around for it again, but maybe someone can beat me to it.

edit: google never ceases to amaze me. first hit on a search for "7.3 idm wiring test"

http://www.gbreman.com/techbulletin_103.html

 

Thanks for finding that write up, i will try that next. Could the electrical part on the IPR be bad and cause that, when i changed the IPR shaft portion where the electrical part slides over it was real dirty. I haven't tried unplugging the map sensor or ICP yet.