I have had my 1995 Chevy Blazer 4x4 4.3L V6 for about a year now. When I first got the truck it was running great and I would get about 300 miles to a full tank of gas. About six months into having the truck it was stolen and they drove the crap out of it and got it stuck in some mud. Once I finally got it back the truck started to run very rough and went down to about 200 miles to a full tank. I have replaced everything from the fuel filter, numerous sensors including O2, plugs, wires, cap, and rotor. Now the truck is running terrible, less than 100 miles to a full tank, back firing, and black soot coming from the tail pipe along with very strong gas smell. I have been told the plastic lines on the CPI/Spider go bad and these trucks are known for it. Now that have done some more research, other issues could be less expensive gaskets and fuel regulator. I just need some suggestions for what would be my best bet because it's our only vehicle and what gets me to work and back. I don't want to tear apart and not be able to get it back together if the parts become too expensive. What should I do to keep this inexpensive and short? Thank you for you time and look forward to some direction in where to begin.

 

Sounds kind of like a fuel pressure regulator is leaking or you have one or more noozles on your injector spider stuck open. We pulled one out of a 1998 engine with 119K miles and from the intake and plugs it must to have still be working fine when the engine was pulled.

Today I will take a look at the 1998 engine spider that we pulled out of the chassis yesterday. It has 524K miles and I think is the OEM spider. It is main issue was a stuck valve but until that it ran really well.

 

1995 was a split year and used two different types of injection systems, and three different types of engine controls. The diagnostic and repair procedures are substantially different for each one. We need to know which system you have to guide you through diagnosis & repair.

Early production 1995 CMFI:



Late production 1995 & newer CSFI: