Tach off and on, runs bad, ...
 

The tach comes and goes, MIL on, error code 341, i replaced the camshaft sensor, did not fix the problem. Engine "misses" especially when cold, runs poorly, very weak..
Any ideas?

crank position sensor maybe. Not sure if your 01 has one. I had a 99 did the same thing it was the crank position sensor behind the starter.

I second that barryb.. my 99 did that and it eventually left me stranded at a traffic light.. crank position sensor was bad. she has ran like a champ ever since

Thanks, that was my thought as well. Even went and bought a new one. Alas, my truck does not have one... Returning part today

cam sensor on that year

Exactly correct, Pap. I've replaced the cam sensor That was first step...
I also "hot wired" the VP44 and it starts and idles smoothly no hiccups.
I'm thinking something from the computer is telling it to behave badly....

we are seeing alot of computers failing

Hmmm Not good Any way to check for that other than swap out?

very hard to fig out sometimes.

I also get a 1690 code : Fuel Injection pump crankshaft sensor does not agree with ECM crankshaft position sensor

Course, mine uses the camshaft pos sensor for that info...

still getting 341: camshaft pos sensor Range/Performance error

Could be a bad sensor. I had mine go out, bought a new one, it went bad in less that 10,000 miles, the second one has lasted over 60,000, both bought from the Cummins parts counter. they are a bitc* to replace.

For anyone following this thread:

Turns out the half moon key from the Fuel inj. pump installed last year came out and the lock washer broke in half, the nut retightened ????? I haven't figured out the *how* of that yet... anyway, the pieces fell into the gears, chipped teeth on the vacuum pump and knarled up the slots on the tone wheel which is on the back side of the camshaft gear...

I fixed it. Yes, It was a b*tch, and i have pics if it will ever help anyone else, let me know..

Thanks for your input, everyone.