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920bratwurst

Hello,

I am having an issue with a Cummins ISX cm870. It had showed up to me with a new turbo,new intercooler and a bunch of new sensors installed. The main issue is that under high idle or when driving the turbo will spool up, seem to be working, and than drop on its face and exhaust before respooling up and repeating this turbo loop. It seems to be building to much exhaust pressure, because if I unplug the manifold pressure sensor it no longer acts this way at high idle, but i do not want to drive it this way. It was having a pulsing/loping idle as well, but after reflashing the ECM to the most current insite update, it no longer lopes at idle. The barometric was skewed reading 23.6, so i replaced this and it reads accurately now. I was leary of the turbo control actuator box acting up so I have checked with a guage the inlet air pressure and swapped the box with a sister truck. I checked the exhaust manifold sensor tube, and it is free of restrictions. I notice it gives an egr differential psi derate going on and off as well on the data on insite when throttling. Hoping to have a little help with this problem child, I feel I am missing something simple here.

Thank You