P0300 code on 2001 Chevrolet Venture with 3.4L engine

Symptoms:

Poor gas mileage together with rough idle rpm. When scanned showed random misfire P0300 code occurring after engine warmed up. Also has erratic acceleration, cutting out and sometimes stalling.

Basic Concept:

The easiest way to check this code is to verify the fuel system. The fuel regulator that sits on top of the engine can be disconnected by removing the vacuum hose connected to it. It can then be driven and observe if the symptoms will go away. Other test includes monitoring the fuel pressure while car is road tested to check performance of the fuel pump.

Repair Strategy:

To test the fuel regulator, hook up a fuel pressure tester at the fuel rail and record it. While idling, remove the vacuum hose during idle and fuel pressure should increase at least 10%. Also check for presence of gas in the vacuum hose that will indicate deterioration of the fuel regulator. On the same token, the fuel pump pressure can be tested and compared to specs by contacting ATS.