2012 Isx15 acting stupid please help

[Rawze]

A lot to unpack there...

== The thermostat is supposed to be 185-F from cummins. Quite often when someone replaces the thermostat.. they do not replace that brass ring (or they do not install the new one properly, damaging it) in the bottom of the thermostat housing and this causes them to run hot all the time or overheat.

== Assume the program is garbage until you have it reviewed. More than 90% of all delete programs are. It needs to be copied out of the ecm and e-mailed to me for a proper review of what someone did in there.

== The EGR cooler COOLANT CIRCUIT CANNOT BE BLOCKED OFF!!!.. It is really hard on the water pump + it will make cylinder 5 and 6 run hotter than normal, eventually causing engine damage. - So if some idiot removed the EGR cooler, I hope like h#ell they put a coolant hose (3/4") from the water pump to the place on the block where the eGR cooler used to be.

== DON'T trust the inframe. VERY FEW repair shops any more will rebuild an isx worth a stick any more. Matter of fact, if someone told me it was freshly inframed.. I would have walked away from it in a hurry.

Sounds like you bought into a can of worms to me so far.