Not sure what to think. All is well until I head down a hill and the torque converter unlocks. Then the rpm begins to hunt up and down quite harshly. Also noticed when accelerating, lift foot and rpm increases then drops off. Anyone experianced anything like this before?

Yes, check for codes
I suspect DTC 036

Thats the ONLY scenario that makes this happen?

PCM is trying to control engine speed, torque from the transmission is turning the engine and the PCM 'thinks' the engine is overly reacting and reacts by over exaggerating the change in fuel quantity. If you hook a scanner up to it you will see what I mean if you watch the delivery quantity while its happening.

Solution...I'd try an updated PROM.

Thanks for your imput. Found the problem to be a mechanical fault in the injector pump. Changed out the pump. on the road again and Momma is happy.

Mechanical fault sounds like fuel solenoid armature wearing out, same as code 036.
Glad to hear it's running again.

Hey guys I'm back and what would be the cause if no codes were thrown and it's a mechanical pump? I have a bad feeling I know the answer but want to hear it from someone else.
Mark

Just thought I would give my imput on my experiance when my truck was surging last fall. I had a new injector pump put in it in the spring of 04 and it started surging in the fall of 04. I contacted our injector fell and he told me to get some lubricate to put in my tank that valve was probably sticking. We did that and haven't had a problem since. He also told me to make sure I change my fuel filter regular (every oil change) because in our area we tend to get bad diesel (too much water in it because it sits for soo long). It may not be the problem but I thought I tell you anyway.

Good luck!

Adding lubricant is the best way to increase your IP's lifespan.

My blazer has been doing that buck surge decelleration thing for years now. I think of it as it's cute little way of reminding me that it needs either a quart of 30w in the next tank or some additive with lubricity features....My $.02

Thanks guys for the helpful info, especially the fact that the surging went on for three years.:-) Could not afford new IP and injectors right now and do not want to have to do it twice(labor wise). I guess I need to go back to the stanadyne products and get off of the power service stuff. Stanadyne has always seemed to quiet my IP down and seemed to run smoother but the power service is easier to get. Time to get off my but and drive down to the hard to find shop to get the good stuff(not to mention it's the place for me to get my new IP and injectors when I need them).
Mark