Dealer just installed a short block a few days ago due to low oil pressure / oil consumption issue. Car has much better response in terms of power and acceleration, but still has quirks. At idle when the electric cooling fan cycles on and off the the engine RPM gets erratic. It seems as though the engine or electrical system isn't responding correclty to the increased electrical load. Most cars have a dip in the RPM then recover quickly. My dash lights dim and the oil pressure starts to drop. The engine RPM surges and lopes for several minutes. After having an engine replaced and then having more quirks pop up it makes me wonder if I have a problem with ECU or ignition coils or fuel injectors that only happens at idle. Does this car have an electrical or mechanical oil pump?