So I have a few fuel issues i need worked out. 95 4WD 4.3 CPI. I was running like crap, so I thought I would pull the upper plenum as well as the EGR valve and clean/inspect everything. EGR had massive chunks of carbon in it. I probably shouldve spent the few extra bucks and bought a screened gasket instead of using the one in the engine gasket kit from NAPA. Lesson learned. Second, I tested the fuel pressure, but saw that it was dropping at an alarming rate with KOEO. My guess is this is where the bulk of my problems are coming from. A quick look showed me that my schrader valve was leaking. Not just at the threads but THROUGH the valve itself. Not cool, considering its right next the the distributor. So I fashioned up a bolt and some washers and plugged it for now, until I can get a new valve. Third, I have the dreaded "multi-colored intake" issue. Drivers side was generally a satin aluminum color, while passenger side was golden brown with a lot of carbon. I suspect a bad regulator, but arent the colors supposed to be the other way around if the regulator is bad (aluminum on passenger side, carbon on drivers side)? Anyway, I removed the IAC, TPS, EGR, butterfly, and every poppet and cleaned the snot out of them. My question is do you think the FPR is the likely culprit? Im going to replace it anyway, but dont want to be chasing my tail all afternoon. Thanks again.

Oh, forgot to ask the main question. When I removed each poppet, it looked like there was a place on the poppet and in the plenum for an O-ring. Looked on a couple websites and couldnt find anyone selling them. Are there o-rings on these things?

 

Solved driveablilty issues. FPR and thorough cleaning of sensors did it. Still curious about the o-rings though.

 

I know I've answered this question at least twice. There are no o-rings for the poppet nozzles. There is no reason to have o-rings given that the plenum is sealed.

I'd keep a close eye on your fuel pressure leak down rate. The CPI spider & 'nut kit' do not like to be disturbed. You are likely to have an internal leak that, while it may not affect the operation of the engine now, eventually will become a problem.