Well, time has come to tear into my 94.5 PSD. Had some strange and intermittent issues with not running well, no power and hard starting. Dragged the bleedin' thing home on a trailer and parked it. As of several weeks ago, no start at all. So it has now been sitting since the first week of November-2011 and it's time to figure it out. HPOP is full and stays full, the tach does jump a bit when attempting to start though I do have a new CPS that I figured wouldn't hurt to install.
When all of the problems began, I had CPS sensor and Low Voltage codes and the ALT/CHARGE light flashed briefly. That light didn't stay on though. Also had an Exhaust Backpressure Valve code.
First question. Is there any additive that I can use to eliminate, or at least reduce the likely algae in my fuel system? Should I just drain the whole system and start fresh? That's gonna suck if so.
Next question. I am already planning on oil, oil filter and fuel filter changes as part of the diagnostic process for the no start. What other filters/parts should I change to avoid or minimize potentially buggering up the injectors with said algae?
I know it leaks fuel from the fuel bowl and has a few oil leaks in the common spots. I planned to rebuild the bowl and use the good seals and hoses. I'm already planning to pull the valve covers since there are leaks on both sides from there. Also looking at new hoses for the turbo to manifold connections. Never did see above 12 PSI on my boost gauge. Any other suggestions while I'm in there? New injector o-rings?
Next question. How does one go about doing the actual "Buzz test"? Do I need specialized equipment? A specific scan tool?
Truck is a 94.5 dually, five-speed crew cab. Ran super until it didn't.

Has approximately 200k on it.
Thanks guys.
By the way, anybody in the Bremerton/Port Orchard, WA area that would like to get greasy in exchange for some help on their ride sometime, you are welcome to PM me... Just sayin'...