In general, I'd say yes, you need it...

Yer probly talkin about one of the vacuum switching solenoids in that area. I'm guessing that you probably have got some vacuum hose issues, maybe missing hoses, causing vacuum leak. Yeah, that could screw up running I guess, but I'd think it would run lean.

One of those solenoids switches vacuum to the fuel pressure regulator, increasing the pressure under certain conditions. Maybe you've got high pressure all the time causing a rich condition ...

I'll wait for pics!


C/YA!
Jeff
'88 Trooper
2DR LWB 4ZE1 5SP
bone stock DD