Thanks for your response and support! It's an early '94 IDI non turbo. I'm running a greasecar system with some modifications. I have three valves for diesel, veggie, and purge mode. I'm about to go off the grid/unable to email or work on my truck for a week so I'll have to put things on hold. I just ordered a injector return line kit that should be at my house when I get home next Wednesday. That was a fairly inexpensive thing to try and all the return stuff looked old and rotten anyway. I'm gonna check the check valve in the return line to the IP next week. I saw in a video that debris in that could be an indicator of a failing IP. Stay with me. I'll be back in a week! See you then!