P1218 Chevrolet -

Question

what could cause the p 1218 injection pump calibration circuit problem I just replaced the ecm

Answer 1

P1218 Injection pump calibration circuit

If you just replaced the ECM the ECM does not have a valid resistor value and the ECM should relearn its resistor value with every ignition cycle, the resistor is internal of the injection pump this may just be a intermittent condition. As it relearns its value it should clear up.