newbie with a problem help please

chevy123 · June 6, 2006

i recently replaced the motor on my 93 gmc 2500 and it was burning a lot of oil i bought the long block from napa they said they would replace the motor under warranty for no charge now i got it back i am getting multiple codes and a erratic idle also the prom number keeps changing at a idle when i have my scanner hooked up i took the truck back and they replaced a ground and the pcm still have the erratic idle problem and the prom still changes but not getting as many codes kind of long but any help or suggestions would be greatly appreciated

chevy123 · June 7, 2006

it was setting codes for o2 iac tps knock nap lean and the prom kept changing while looking at data after the new pcm and ground map and lean codes come back and there was one more i cant rember theprom still changes as well i can clear the codes and then diffrent ones will show up

chevy123 · June 8, 2006

Double check your harnesses to make sure none are pinched. You could still have a ground that is not hooked up. Both are very easy to overlook.

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The battery ground is on the blockoff plate for the mechanical fuel pump. there is a new ground strap that goes from the niddle side of the passenger head to the firewall, their is also the 2-3 grounds for the sensors that are bolted to the thermostat housing.

When I hook up my genisys to the vehicle all of the readings seem to be erratic and one thing I notice that seems to be very confusing is the fact that the prom ID on the screen starts with 5195 then it will flash to **** then flash to 3 or 4 different numbers. Could that be that the ECM had been shorted out some what and caused me to have all thes erratic readings and to have the truck drive some what rough?