I have a 93 S-10 Blazer and it has some major problems. If you sit at a light, it shakes really bad and has trouble getting up and going after the light turns green. It backfires some while driving and it has thick black exhaust after you get going from the light. Any ideas?

 

kinda sounds like the egr valve is stuck open maybe

 

Yea, that does sound like the problem, mine did that when I first picked it up, after a new coil, and rotor, plugs wires, and cleaning out the EGR Valve,and new oilthe smoking went away, the idle smoothed out etc...it still shakes a little bit while idling, so Its still not 100%, but I am working on it.when I have another full day off, I am going to pull the IAC and clean it, and seafoam the intake and maybe pull the plugs and check the gap cause maybe I screwed them up when I gapped them. If that doesn't work, I have a GM Extended warranty so I will take it in and have them look at it. Anyways, hope it has helped a little bit.

 

I would also check your mounts (engine, trany, t-case) these can cause a shake at idel or running.
Other things could be: fly wheel, torque converter, drive shaft, trany, metal fan blade, low idel

 

If you have a CPI intake you could have a fuel leak in the spider/pressure regulator/ or the internal fuel lines to the spider (Nut Kit)..

This link will show what I am talking about...

https://blazerforum.com/m_7118/mpage...PI/tm.htm#7118

 

It does sound like a possible sticking EGR valve......any codes?............and probably fouled plugs by now.