So I posted this awhile back but it's still doing it. So my friend has an 03 1500 4.7 and anytime it gets over 3k it just sputters and shakes till you left off. He just replaced the fuel pump hoping it was the problem. It didn't fix it, I check the codes it's throwing and it's a p0420 o2 sensor, a p0344 camshaft intermittent, and a p0340 camshaft position. He really needs help with this so any help would be great.

 

Check the wiring harness for any frays or cut wires. Maybe replace the crankshaft and camshaft position sensors.

 

Have him change the spark plugs. Basic coppers and they are due every 30kmi.

Cut-out past 3krpms sounds like spark problems amongst a few other items.(crank or cam sensor?)

Change the plugs out. They are pretty cheap. Walmart Autolites are $2.34 for 2.

 

Well we got it fixed, replaced the cam and crank sensors cause everyone said to do both.