The code p0300 - Random Misfire started occurring about 2 months or 7,000 miles after a engine head rebuild due to a stripped spark plug thread in cylinder 2. The car ran just fine after the top half rebuild until some 7,000 mile were racked up. As I could not diagnose the problem, I took it to the dealer who then advised that I replace the spark plug wires, boots, plugs and PCV valve. This was done but the problem still occurs. Both coils were tested and so was the cylinder compression which were normal. The dealer then proceeded to recalibrate the ECU and after which it ran fine for 2 days. As recommended by the dealer, I cleaned the throttle body,making sure to capture any excess cleaning fluid with a clean towel under the butterfly opening. After drying and re-assembly of the air inlet housing (the battery was left connected during this procedure) the car ran fine for another 40 or so miles (a full day). Then, the Random Misfire started again. The car is still not fixed and I have spent a lot of money going nowhere. Can you offer me any suggestiosn as to what could be wrong. Thanks.
Jun 24, 2010 at 1:13 PM