POS s10 troubleshooting

My s10, with a 4.3l Vortec, is acting funny. It requires me to give it gas to start up, sometimes dies before I’ve backed down my driveway, or when I put it into drive. Idles rough, and smells of gas when driving. I’ve ran sea foam to clean the carb already. Drives fine, once she’s going, just the gas smell and a serious lack of power. She dies if I try to goose any, as well. Any suggestions??

What carburetor are you posting about? That model S10 would not have a carb from the factory, it would have fuel injection.

So why don’t you explain more about the year, the miles and the mods done to your truck other than the obvious from the picture cowl induction hood scoop?


What model year?

1996 or 1997?

Does it have one of the various central fuel injection systems . . . there were quite a few, and once you tell us the model year, I’ll have some more idea where this may be going?

There’s no way you have a carburetor . . . I can see from the picture that the truck is far too new for that.

I’m pretty sure you’ve got a fuel pressure test port in your engine bay

If you have a gauge, hook it up and let us know what you’re reading

Is the check engine light illuminated with the engine running?

The check engine is on. And, I’ll show you what’s going on under the hood. It’s a 94, but it’s not stock and I didn’t build her.

I don’t have anything to check that port out, personally. But I’ll look around!

When I got her plugged in, the reader at O’Riely’s won’t read. The wiring was a mess when I bought it.

Full disclosure, I’m just learning as I go along. I was told it has a carb, it looks like what I’ve seen. But, the engine isn’t stock. Here is a picture:

I believe that is Throttle Body Injection (TBI) with 2 injectors. The enclosure and bracket on top do not look stock. I have the same setup in my 93 Caprice with a 5.0 V8. Never had any problems with it. Perhaps an S10 forum can help with the TBI issues.

Ed B.

A 94 will not have an OBD ll port , those did not come along until 96 for most cars, 95 for some GMs. I am not familiar with GMs, leaking fuel pressure regulator maybe?


Your truck seems to be 2 - 3 years older than I initially thought

you’ve got TBI . . . which to some people looks like a carburetor

I’m not entirely sure. I looked up a 1994 S-10 4.3 on rockauto . . . because op has not yet told us the model year, so I made a guess. And it shows a round air cleaner, which is what I would expect here

O’Reilly won’t be able to help you pull codes because your truck definitely isn’t OBD2-compliant. And those parts stores usually only have OBD2 code readers, which doesn’t apply to your situation. Although you didn’t tell us the model year, as far as I know, there was no such thing as an OBD2-compliant S10 with a 4.3 TBI engine.

There’s a procedure for counting blinks, in regards to retrieving trouble codes. And there’s also scanners and code readers which have adapters for pulling codes from those earlier OBD1 vehicles, such as yours.

As for the gas smell and lack of power, have you ruled out leaking injectors yet?

I can see two of them in the center of your picture

There’s also a fuel pressure regulator in the lower part of that TBI unit. Could also be bad and/or leaking

I’m just mentioning this because you said you smelled raw gas, so there might actually be raw gas, as in a fuel leak . . . ?


Could it just be a funky o2 sensor? Telling the engine it’s lean, thus pouring too much in?

With all due respect…that Check Engine Light is trying to tell you what the problem is, or at least give you a direction. Until you know what has triggered the light, you’re just shooting in the dark.

Get that code read (or count the flashes), and then go from there.

I think it was Throttle-body-Injection (TBI). They were temperamental.

Originally a dog-legged threaded rod was attached to the throttle body case to attach the breather. I can only imagine that someone lost the rod and built that piece of hardware to replace it. That throttle body is easier to rebuild than most carburetors and the diaphragm in them was deteriorated, most likely from ethanol fuel, on the vast majority of those that I rebuilt.

The plug in for the meter didn’t work. I should just fix that first?

I know, I know… my truck is turning out to be a complete shit-show.

So, if that’s the case, what do I do to fix my problem?

I’m new to all this, but I’m trying to learn.

Read the codes and follow standard diagnostic test to determine the cause and if the throttle body is pouring enormous quantities of fuel into the engine it’s likely a bad throttle body which you can replace with a factory rebuilt unit or rebuild it yourself.

Even someone very familiar with the system you have cannot guess what the cause of your problem is without investigating and unless you live in the 38804 zip code I won’t be available. You need to do the leg work and honestly, when you do you likely won’t need any help from us with the diagnosis.