Need some help/thoughts 2002 QC LB 2500 ram 4x4 5.9gas headers, K&N, MSD (Igint, Coil, Plug Wires)Superchip. 103,000 miles. Well maintained does not smoke or make any noise, Unpluged PVC Hose and the pass side hose blocked off held hand over oil filler port the engine built up pressure not vac. Intake gasket should be good, never has used oil,plugs are clean. Truck wt. #6500 4:10 gears Michelin LT265 on a recent trip 325mi got 13.85 mpg. Heres the prob, keeps giving a p0301 code (#1 cyl misfire) New cap and rotor, new plug, changed out #1 plug wire, new injector, stll same code. Using an Infered thermometer #1 cyl runs about 160 degs cooler than #2 and idels rough. What are your thoughts?

Mr.Runum

What did that #1 cyl spark plug look like?

Sounds electrical or sensor related.

#1 looked good and I even had a new one. I put the plug on the engine and started, had a good blue spark. Yet the header tube #1 is still 192deg vs #2@360deg at idel.

Do a compression test, just to ward off possibility of internal issues.

I wouldn't be surprised if it wasn't the cam or crank position sensor, or another like sensor. Do you notice any missing, or can you hear it through the exhaust? Have you tried clearing the code?

I have cleared the code with my superchip. it does miss and you can hear it feel it at idle. A compression test is about the only thing I have not done yet. Maybe a bent valve, bad cam?

Mr.Runum

Ran a compression test on #1,2,3 cyl 2 &3 were at 175psi cyl #1 was 150psi.

Mr.Runum

150 should be fine. Mine had only 75 psi, and mis at idle when I found a valve to be burnt. I wonder how your #1 injector is.

He stated new injector. Maybe it is faulty??????

Possibly, but since a code for a sensor isnt popping up, I would still be inclined to check into a slight intake gasket leak.

The 5.2/5.9 engines do have some tendancy to kill these over time, which causes detontation, oil consumption issues and some slight misfiring.