QuestionI am getting a misfire above 3200 rpm on the highway... can't climb hills etc. runs fine when cold... misfires when warmed up... got a code of p0300 also...thought it was the cam position sensor, but thats ok.
AnswerThat is known to me as the extortion code. Unfortunately is a code that can be caused by multiple cylinder misfires which tells you something. All of the cylinders have "skipped" more than their fair share. Start with the easy/simple stuff. However, this code has been known to get very expensive. Make no bones about it, it's an Easter Egg hunt.
1. Check the temperature of the inflow and outflow of the catalytic converter. The temperature should be 100 degrees higher. Infrared thermometer is used. Might be able to find a shop to check it as an "inspection."
2. Tune up the truck(plugs, wires, test the coil packs). At least Inspect the wires for damages or cracks. Wouldn't hurt to get handy with an ohm meter to some of you're sensors like the throttle position sensor. But try to stay away from throwing parts.
3. Check the Egr System, sensors rand all.
4. Check the fuel pressure at an idle ,mid throttle, and etc.
5. Look for vacuum leaks. You will also need to do both a compression test and a leak down test. The valves may need work.
Let me know how "Phase 1" of this problem goes in the numeric order listed. How many miles are on the truck?
