Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
DTC P0300 SYSTEM DESCRIPTION The powertrain control module (PCM) uses information from the crankshaft position (CKP) sensor and the ignition control (IC) module in order to determine when an engine misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the PCM is able to detect individual misfire events. A misfire rate that is high enough can cause the 3-way catalytic converter (TWC) to overheat under certain driving conditions. The malfunction indicator lamp (MIL) will flash ON and OFF when the conditions for TWC overheating are present. If the PCM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, DTC P0300 will set. CONDITIONS FOR RUNNING THE DTC
CONDITIONS FOR SETTING THE DTC The PCM is detecting a crankshaft rotation speed variation indicating a misfire sufficient to cause emission levels to exceed mandated standards. ACTION TAKEN WHEN THE DTC SETS
CONDITIONS FOR CLEARING THE MIL/DTC
I have a OBD II AutoScanner so what is my next step? Do I follow your test discription step by step?
OK. so i changed the spark plugs, changed the control modulator, and changed the catalytic converter but it still misfires when I start to slow down and the car goes into idle. The check engine light starts blinking then stops when it stops misfiring at a higher rpm. Then when I slow down at the traffic light it starts again. I did not check the fuel injectors. What should I do next?
with a fuel pressure gauge available at most part stores and it threads into the test port on the fuel rail
We will have to pinpoint what the engine is missing.
I just recently purchased a 2004 Tahoe with 155000 miles