I have a 94 s10 4x4 v6 vortec. Symptoms are that it stutters and stalls (like its out of gas, but the tank is full and my gas gauge is working) on acceleration. If I pump the gas, it pops and stutters, but if I let of the gas completely and slowly press the gas pedal it will go until I hit about 40mph and it will do it again, then again, as soon as it starts stalling if I floor it, then it picks up and goes but at the top of the rmp range before it shifts there is a slight miss.

Two weeks ago I did a tune up, new plugs, wires, distributer cap, points, air filter and fuel filter. I have checked vacuum lines and there are no leaks. I put my stethascope on the plenum and can hear the injectors clicking, fuel pressure is within specs and have cleaned out the EGR.

I am stumped, so if any of you have any other suggestions I would be gratefull for a reply.

Thanks

 

Just out of curiosity could fuel injector cleaner create this problem. This is the only thing I have done different since this started. Also, if I were to have a fuel leak under the plenum wouldnt it throw a code?

Thanks

 

On the codes, not all the time. Most often, the leak isn't enough for the PCM to notice. Once it goes real bad, it'll just not run.

And no, I do not believe that running a fuel injector cleaner could cause this type of problem.

Your CPI motor only has 1 injector that is batch fired.

 

I have a 3.3 lt doing the same thing. Found it was the ACC Sensor and the Early Fuel Evaporation Relay.
Odd too due to its in a 93 Century (its the only year GM did not use an EGR valve).
On a blazer, I believe its called the ACT (air charge temp) Sensor.

Sometimes these things are hard to find. Most Bearcat Scanners will not detect this durring testing.
Its something you end up finding due to trial and error.

Would be worth it also to go buy a Fuel Pressure Tester. Seems loads of people here push these type of issues to the fuel pump.

Good luck and let us know what you find.

 

Thanks for the replies. This is strange though. Last week when I was working on it, after driving it around for a while and checking things I was getting low on fuel (just below 1/4 tank). Now then, in my cruising around the web looking at auto troubleshooting sites I came across a forum and one particular post was a guy who had a Blazer 94 or 95 and he said something to the effect that when the tank gets below 1/4 the fuel pump starts to be exposed and since the fuel is what cools the pump it can start to get hot and act up. So, in desperation, on one of my test runs I headed to the gas station and filled it up. Well, on the way home, which is about 7 miles, it ran just fine, didnt stall, hesitate, nothing. I drove it around for an hour and it never did it again. I figured maybe the gas gauge was broken or I was actually running into this overheat problem with the fuel pump. It ran fine all week, until yestreday when my wife was coming home from work it started acting up again. The first thing I asked was how much fuel was in the tank and it was at half a tank. I have doen a fuel pressure test and its within specs.

I have a feeling that the problem I am having is something really simple and I just am not seeing it so before I go ripping the fuel tank out and changing the pump I am going to run some Seafoam through it. Just to verify the other posts I read, you suck this stuff up through the PCV hose correct? Pour some in the tank and in the oil?

Once again thanks for your responses.
Geoff

 

Have a few more questions for you all. Where is the fuel pressure regulator on the 94? Do any of you know where you can get those fuel intake and return lines other than at the dealer ($96.00) I pulled the plenum last week to check the lines and when I pulled them off the clip that secures them to the cpi unit broke. Any suggestions for fixing that without having to buy the whole unit? The hoses are okay, no leaks, so I dont really want to spend that kind of money just for a clip if I dont need to. The thing still doesnt run, it wll idle all day but as soon as you put it in drive you go about twenty feet it dies.

Thanks