Hello,
Looking for some experienced 4.3 troubleshooting help.

I have a 1993 Blazer vin Z (4.3 TBI), 5 spd manual trans. 153k miles.

When I turn the key off, the engine stutters. Just a little. Kind of like dieseling, but not that bad. I have seen throttle body injectors bleed on other vehicles and cause dieseling, but I don't see any seepage on mine, at least not of that significant quantity.

The engine idles smooth revs smooth. Only a slight stutter when cut off.

Is there something else that might cause this, that I can check? I have checked the timing (with the wire unplugged, timing was fine) and I changed the plugs, there was some fouling.

I suspect there might be some buildup in the heads and was going to run some fuel treatment (something like seafoam) in the gas.

I have been working out the kinks from this truck, and am about to tag and insure it and start driving. It has been a project for almost a year (mostly electrical/body work). I thought driving it might help clean up the engine, but I also considered that driving it might exacerbate the problem.

If it may be the injectors bleeding, does anyone know what size o-ring would need replaced, or do I have to replace the entire injector?

I think I will have someone take a video and maybe I could post it, if that would help. Thanks in advance for any insight...

 

Well, put about 25 miles on it today, figuring some road time might help clean out the systems, or at least exacerbate the problem enough to identify it.

However, it didn't work out quite as I expected.

Got a freeze plug leaking behind the starter, which is new. Not surprised that there is a new coolant issue, since it had a new water pump on it and a bypassed heater core (since repaired).

I guess I will attempt replacement in the vehicle. Although it will not be the end of the world if I have to pull the motor. Then I can replace all of them at once, check out some seals, and get a look at the clutch (the pedal is all the way at the floor, but it shifts well. don't know if the clutch is almost worn out or if that can be adjusted somehow; with 153k it is possible that the clutch is original).

So the stuttering will have to wait until I can burn some more miles on it. Still thinking its an injector bleeding issue, but will have to wait to confirm my theory.

 

just got a 94 auto 4.3
it drove about 40 miles and then stalled. had been informed upon purchasing the thing, that it had the symptom of stalling, and that the spider injectors wore out on them a lot.

replaced the spider injector, and thus far, it has been riding well. rough idle.
i've never dealt with timing belt or any of that sort of stuff. not sure what sort of injector you have on your throttle body.

i agree @ 150k that it might be the original clutch. i might have the original clutch in a 92 mazda of mine with 430000km. pends how it's driven. not sure about adjusting clutch pedal. have had to replace a slave cylinder twice due to a leaky seal. obviously your reservoir is topped?

later.