Engine/Transmission (1998.5 - 2002) LP pressure fluxuations at idle, ok at wot?

[SCox]

3rd lift pump is going at under 1000k on it. Anyways, this one is dying a little differently. I get big fluxuations at idle(3psi to 14 psi), once on the throttle it acts fine... I assume because once vp demands the fuel it's vacuum is helping out?? No underlying problems here I hope, let me know if anyone thinks otherwise



Thanks

Steve

 

[Texas Diesel]

Same here, just like you describe.



The problem turned out to be a bad overflow / pressure regulator / whatever valve in the VP-44.



Got another one and problem solved.



I didnt even bother too disassemble it just glad the problem is fixed.