I have been having trouble with my 3.4 recently (180k) Timing belt, etc done at 170k. Originally the engine had some work done to replace the valve cover and intake plenum gaskets. After this was done, at around 4k RPM's, the engine would buck and jerk and not go above 4k RPM's. I kept it under 4k RPM's the rest of the drive, but when I drove it again, the same thing happened followed shortly by the engine cutting out on me. I couldn't get it started again

I took it into a shop and they determined it was the harmonic balancer and replaced it.

I picked up the truck today and before I could drive 5 miles, i had the same bucking/ jerking symptoms followed by the engine completely dying on me.

After about 30 minutes (a.k.a. the tow truck ride) the engine started again and ran very rough at idle and cut out completely when I gave it any gas.

I did the spark plugs, wires, and a coil pack within the past 20k miles.

Any ideas would be greatly appreciated.

 

Did they plug the crank angle sensor in?

Did they torque the balancer to 217ft lbs?

 

I don't know about the crank angle sensor, but I asked and they did torque it to 217 ft/lbs with loc tite

 

Ended up being a ruptured fuel line, thus no fuel pressure

 

i hate those shops that just throw something on, a harmonic balancer for a bucking situation, wtf.

 

That really sounds like some nooby typed 'engine rough' into a computer and did the first thing on the list. If you let him keep going you could have had a whole new engine by now....