Bought a 94 with 6.5. After driving 1/8 mile or so service engine code comes on. Will go away after turning off. Have never had Chevy Diesel before but seems to run ok. Little lounder then my Ford 6.0 Diesel (Yes I know ford) no way near the power but seems to run ok. Bought a ODB1 scanner tonight and showing a few codes.

DTC 97 Acb modifier Out Of Limits for Cyl 7

DTC 55 PowerTrain Control Modual A/D fault.

Any one tell me what they mean? Google not realy helping.

Could it be Injector issue on Cyl 7 ?

Also read a little where I should update cooling? They known for running hot? this one seems to run cold. but then again dead of winter around here.

Thanks for