93 S10 Blazer 4.3L W Vin with CPI. Got this ole girl back on the road several months ago after sitting for a several years. At that time I replaced the fuel filter, suel pump and sending unit, and the fuel injector. It ran fine for a couple of months.

About 2 months ago it started sputtering and back firing through the plenum and it turned out it was a clogged fuel filter. Ran fine for about a month after replacing it then it started losing power, sputtering, and cutting back. I thought it was the fuel filter again since there seemed to be a lot of rust in the fuel tank and the symptoms were simular. I replaced the filter again but this time it did not fix the problem.

After reading several post on here about fuel leaking under the plenum I decided to check. After removing the plenum I found it to be black with carbon build up and wet. There was some puddling at the bottom but I'm not sure if it is gas or oil since it is black from the carbon. It seems to thin to be oil. Anyway, I replaced the fuel lines that feed into the injector. Put everything back together and here I am with the same issue still.

From reading; isn't it supposes to be pretty much clean and dry under the plenum? What else could be causing the symptoms?

 

EGR valve stuck open..Yeah it should be pretty dry under the plenum, but it could be from the constant exhaust blowing through the intake port..

If you still have the plenum off you can take a piece of hose that fits tight in the port coming in from the EGR valve and see if you can blow through it, if you can the EGR valve is open. You'll have to take it off and get the piece of carbon out that's holding the pinion open.

 

I have alread put the plenum back on. Is another way to test the EGR valve?

 

The only other way I know is to take it off, the EGR valve that is. You'll be able to see if there's carbon in it. I think it's supposed to set a code but I've had it happen a couple of times and NO code..I always install a screened gasket anytime I take the EGR valve off. They help a lot.

It's not an easy job taking it off, at least I don't think it is.. If I were you I'd get a second or third opinion before doing it.

 

ffox is on the money there. A word of caution on cleaning the EGR valve. Do not use any solvent to clean it! It could seep into the diaphram and desolve it! Use a wire brush to clean the opening that goes to the intake. And follow ffox's advice on the screen. Good call!

Also check the distributer cap, rotor, and plugs. If the distributer cap and rotor are worn they will cause your vehicle to stumble quite a bit and you'll think it's fuel related sometimes and will drive you nuts trying to find what is wrong!

Wade

 

I had to replace my EGR Valve due to very similiar problems. I didn't think it was that hard, it's only two bolts. You will have to remove a small brace going from the power steering pump to the passenger side valve cover to work the EGR Valve out. The bolt under the throttle body is a little harder to get to but nothing an extension won't solve. If your vehicle has an electronic EGR (which it should) the wire is on the drivers side and is a little bit of a pain to disconnect and re-connect when finished. I had to put a new one on mine because it had already been removed and cleaned and put back on and it clogged right back up. I found out when I had removed it, the pintle was collapsed and looked to be in very bad condition so I just replaced it. It is a fairly expensive part though, around $170.00 ad Advanced Auto Parts.

 

It is 165.00 at Autozone I was Just Looking into Them, I cleaned Mine with WD-40 before reading about not using Solvents, However The spring Worked great and The EGR wasnt all That dirty inside I did Use a screened gasket from the Help section of parts store was about 8.00.

I am Having The same issue have 2 diff posts as The original post is ongoing and has more than a single issue with The fuel issue resolved, However Im now at a Idling and running issue.

Same Vehicle Though 93 S-10 Blazer 4x4 , 4.3 Liter CPI 262CI Vortec Vin W
Today, I drove Mine to work It Floods and throws a Check engine Light when accelerating Uphill ( The catalytic Converter is Gone Strait Pipe in place )

Please read Through The 2-3 Threads I have. I have Got Great Responses. Some Super info on these issues are in There. Swart and a couple More have Superb Input and I tried to describe The symptoms in detail and update as often as I tried something Different. I am hoping to find out if The Sensors on The Plenum Could Be part of The issue.