misfire
New User
Joined: Apr 2010
Posts: 2
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This was my P0308 experience::
P0308 and P0174 PCM codes not caused by COP or Fuel injector.
We were pulling a 5000lb travel trailer from Las Vegas to Abq and engine started missing badly with the “Check engine” light flashing. Stopped in Kingman and bought a COP and new sparkplug. Let the engine cool down and replaced the plug and swapped COP with #1(Did not use the new COP because the connector was slightly different). Started it up, cleared the codes and it ran fine. Until 10 minutes later after heating up and pulling the trailer. The same codes and misfiring returned. (All the way to Abq with about 8mpg too). Next day, got a new injector from auto zone but it was a different brand (same physical size). I was unsure about the new injector so I put it in #6 and put #6’s in #8. The truck ran fine until it heated up and the same codes came back. I tried to use a noid light to make sure it was getting signal to the injector and the noid light was loose in the connector. I then realized the connector was also loose on the injector. I started the truck and could make the misfire come and go by moving the connector. I could also “feel” the injector clicking or not clicking depending on how I moved the connector. I replaced the connector with a pigtail I got from NAPA ($41.00) and problem solved. Unfortunately the Cat on the driver’s side was clunking and rattling. I had it replaced for $199 and the very knowledgeable guy said consistent misfires would trash the Cat.
P0308 and P0174 PCM codes not caused by COP or Fuel injector.
We were pulling a 5000lb travel trailer from Las Vegas to Abq and engine started missing badly with the “Check engine” light flashing. Stopped in Kingman and bought a COP and new sparkplug. Let the engine cool down and replaced the plug and swapped COP with #1(Did not use the new COP because the connector was slightly different). Started it up, cleared the codes and it ran fine. Until 10 minutes later after heating up and pulling the trailer. The same codes and misfiring returned. (All the way to Abq with about 8mpg too). Next day, got a new injector from auto zone but it was a different brand (same physical size). I was unsure about the new injector so I put it in #6 and put #6’s in #8. The truck ran fine until it heated up and the same codes came back. I tried to use a noid light to make sure it was getting signal to the injector and the noid light was loose in the connector. I then realized the connector was also loose on the injector. I started the truck and could make the misfire come and go by moving the connector. I could also “feel” the injector clicking or not clicking depending on how I moved the connector. I replaced the connector with a pigtail I got from NAPA ($41.00) and problem solved. Unfortunately the Cat on the driver’s side was clunking and rattling. I had it replaced for $199 and the very knowledgeable guy said consistent misfires would trash the Cat.
