Lugging Engine in 99PSD

[crawfordd99]

Hello all,
I'm new to this forum, and am having an issue with my 99 Powerstroke. Its the 7.3L, auto trany, full turboback exhaust, and Hypertech programmer. It was recently converted to burn used veggie oil as well. This problem precedes that mod. 225K miles. Runs well except:

Here is the issue: 3 months ago, the pitch of the engine at idle changed slightly, and the idle speed crept up about 100 RPM's. At low RPMs, both towing and not, and low speed (35-50 MPH), there is a chug in the engine resulting in the whole truck shaking. This happens in 2nd, 3rd and 4th gears, which leads me away from a tranny problem. It feels like the engine is lugging as if it were a manual shifted too early.
My mechanic, who is pretty good, thought is was an exhaust problem, so I replaced the stock system with a full turboback, and it didn't cure the problem. A new K&N air filter didn't help either. I replaced the fuel pump and filter today, and it helped a little, but the shake is still there (insert image of me cussing up a storm going down the road here).
The injectors have been tested, and are pulsing fine (i didn't do that test, but my mechanic did and he said I am OK), the fuel pump is new, and I can't figure out what the heck is going on..........
My thoughts:
1) A sticky valve
2) a bad injector that isn't showing up on a regular test
3) a bad head gasket and I'm losing compression
4) uuuummmmmm???

So that's the first issue.
The second is the veggie oil system. I installed a bed tank (60 gallon), and have a heater core in the tank. The lines are plumbed to a ford stock switching valve, and a ford stock fuel switch. The veggie oil produces white smoke and really crappy power. Really crappy. I have a buddy with the same setup and he gets great power and his engine actually runs better on oil than on diesel. (I have a sneaking suspicion that the idiot who installed it didn't tighten up a coolant hose and I am burning coolant with the grease)
I know this is two topics, but the first is what is really driving me up the wall. Any help is appreciated.......A lot!

[crawfordd99]

Had to go to garrett motorsports, and found out injector on cylinder 1 was shot. It buzzed fine on electric, but they test for mechanical failure there too, and it was off to the great diesel farm in the sky for that bad boy. New bank of injectors later, and a new fuel pump, she will spin all 4 back tires, and haul a log like its not even there....
but Jeez that repair bill sucked........