1990 - DTC 55 - ZR-1 Net Registry Forums

NVRL8TE · 01-16-2022

Hello team,

I recently purchased a 58k mile 1990 ZR-1.

Haibeck chip and a ported top end are the only mods.

It was running great until the other day it started to run rough under light load, and it seems to continue, the higher I take the RPMs.

I ran codes, and it gave me a DTC code 55 "Fuel Monitor Lean".

I have a fuel pressure gauge hooked up, key on engine off, and the pressure goes from 42 PSI, to 20, inside of 30 minutes.

Is this common? I hope I'm looking at fuel pumps as opposed to injectors...

What is the next direction I should take?

01-16-2022	#1
NVRL8TE Join Date: May 2021 Location: Cleveland, OH Posts: 43	1990 - DTC 55 Hello team, I recently purchased a 58k mile 1990 ZR-1. Haibeck chip and a ported top end are the only mods. It was running great until the other day it started to run rough under light load, and it seems to continue, the higher I take the RPMs. I ran codes, and it gave me a DTC code 55 "Fuel Monitor Lean". I have a fuel pressure gauge hooked up, key on engine off, and the pressure goes from 42 PSI, to 20, inside of 30 minutes. Is this common? I hope I'm looking at fuel pumps as opposed to injectors... What is the next direction I should take?