# 1994 Chevy S10 Pickup 4.3L V6 Rough Idle



## blubswillrule (Apr 2, 2013)

Hey guys, y'know, the usual situation here, first time poster requesting help on something... but I've just been banging my head against a wall with this, hoping somebody else may recognize my problem and help bring about a solution.

I have a problem with my 1994 s10 4.3 tbi. When accelerating it runs fine. but when I let off the gas it dies, it looks like the fuel injectors stop spraying fuel so the truck dies out.

Similar problem when starting the truck, when starting the truck no fuel comes out of the fuel injectors. But if I apply gasoline to the throttle body the truck starts and will keep running while accelerating, but again it dies out when I let go of the accelerator.

We've already replaced the fuel filter & fuel pump and resealed the fuel pressure regulator and most of the surrounding seals.

We've already tried replacing a few parts, albeit with used parts...
-Replaced the fuel injectors, seem to work much better now (that is, when they do work)
-Replaced idle air control valve (unsure how to know if it's good or not)
-Replaced throttle position sensor (unsure with this one as well)

The truck will start randomly a few times, then die out after running for 3ish seconds (if you don't push down the accelerator), then it just won't start anymore.

As stated above, really banging my head against a wall on this one.

any and all help is appreciated, Thanks!


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## octaneman (May 13, 2009)

Hi blubswillrule


The symptoms you describe have the appearance that your engine isn't getting the proper fuel ratio. What you need to look at is your Mass Air Flow sensor, dirt and debris get stuck into the sensor giving incorrect data to the computer. Remove the sensor and clear out the debris using MAF sensor cleaner, while your at it clear out any carbon deposits that have built up onto the throttle plate. Do not use carburetor cleaner to clean the sensor or else you risk destroying it. If the problem does not clear up don't assume that the sensor isn't good and you go out to replace it, there are other components that need to be looked at before making a final determination. 


post back your findings.


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## blubswillrule (Apr 2, 2013)

Thanks for the reply!
MAF sensor? I'm not sure my truck has a maf sensor, I'm reading everywhere that only 96 and up have MAF sensors.
It says that MAF sensors replaced the MAP sensors, could the MAP sensor be a cause of the problem?


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## wolfen1086 (Oct 4, 2007)

If yours is TBI then its a MAP sensor, It should be bolted to the side of the air filter housing or on the firewall, (unless Leeroy put it somewhere else on Thursday).
My old Blazer did that a few times and I found a bad connector at the fuel nozzles,


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## octaneman (May 13, 2009)

If your truck has a MAP sensor it wont require any cleaning because its a sealed unit. To know that the map sensor is good first you will inspect the vacuum hose thats connected to it for any breaks or leaks, then you will need a vacuum pump and multimeter to test it.


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## dyn0myt3 (Feb 2, 2016)

I have a 2004 s10 v6 vortec

This morning I cranked it up and the idle was very rough between 1-2500 RPM, bouncing back and forth. It stalled twice before it finally began to idle properly.
Took it to the shop, check on it in AM. 
I use detergent gas, had the throttle body cleaned when I bought it. 
I do have the check engine light on, codes are reported as a mass air flow sensor and a crankshaft sensor. 
It hasn't acted up until now, so looks like its $$ time.
Thanks for your comments.

dyn0myt3


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## bruiser (Jul 30, 2005)

The MAF could be the problem. Crankshaft sensor doesn't really cause any driveability problems, and don't cost much.


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## dyn0myt3 (Feb 2, 2016)

ok, hopefully i can get it fixed.

Thanks.

Dyn0


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