A 1989 4.3 Mess

Hello,

I bought an S-10 Blazer a couple years ago from a guy who said he had rebuilt it.

When I decided to get it running right it was idling waaaaay too high. I tried backing the curb idle screw off and it died. Soooo.... I got into investigating the vacuum. There was nothing but carbon in the throttle body (it was so bad that all the ports were totally clogged). I rebuilt it. I also cleaned the EGR valve and got a new O2 sensor. I don't remember what all I did to be honest; I went through the entire fuel and exhaust systems, and it ran very well.

Skip foward about two years.

One morning I go to start it and the starter crapped out. My starter replacement mess is chronicalled on this board, but that's beside the point. Right before the starter went the truck was violently shaking. I had fueled up right before and figured I got bad gas.

Well, it wasn't bad gas. I've been through the valves. I've got a sticky exhaust valve but it's never caused me any trouble. The idiot didn't adjust the valves after he rebuilt it - I know I should have adjusted them first but I didn't. So I did now. Slight improvement.

I've been going around looking for vacuum leaks, and also found the timing out to 4*. I set it back.

I have a violent shake at idle and when I'm in gear it sometimes dies. I have no power on the road and when I floor it, I get a deep, throaty exhaust sound but no pickup to go with it.

I've given it a thorough tuneup, etc etc so on and so forth. I've not yet checked the EGR though I know that should be one of the first things looked at. I wanted to get my valvetrain inspected and tuned though as it was making some noise.

I have narrowed it down to EGR, vacuum leak I've not found yet, or the ignition module. It sounds like it's just not firing on one cylinder.

Sooo... any ideas? Any and all input is appreciated.

Thank you,

Josh <><

Of course check the EGR, and for vaccum leaks.
Then try an internal steam cleaning with a spray bottle.

Remove the air filter, and spray a mist of water into the opening with the truck running.
Do this for a few minuits, and never let the motor bog right down and stall with too much water.

Make sure both injectors are spraying fuel, easy to see.