I have a '94 Blazer. 4.3L, 4WD. The thing started running like a dog a month or so ago and I found the EGR valve was bad. I replaced the EGR and it ran fine for about a week.

Then, I go out to start it up one morning and it just wouldn't start. A few hours later it started but idles like a turd. No check engine light at all, no trouble codes, nothing.

Anyone have any ideas on what is going on with this thing? Thanks in advance.

 

if its doing the same thing it did before the new egr valve, it could be that the new egr valve is clogged again?... did you put on one of the gaskets with a screen in it when you replaced the egr valve?... they make those to keep particles from clogging and fouling those egr valves.... if you take the egr valve off and clean it and the truck runs fine again for a little bit, i would guess that the egr is getting clogged and suggest you try a gasket with a screen over the hole.... just a guess

 

what nbwebb said. had the same issue with my 93 S10 Blazer. By the time I figured it out I replaced the fuel injection, fuel regulator, MAP sensor, IAC sensor and TPS sensor....

For whatever reaon, mine likes a new IAC about every other year....i must be buying junk ones or something. But it idles soooo much better when all the sensors are working and the egr is clean.

 

Well, she started up today. Gunned the engine a little and black crap came out of the exhaust. Nasty looking gunk too, yuck.

Anyway, I let her idle for a little bit, then drove around the block several times. Darn thing is running and not too bad either. I did notice that when I hit the fuel pedal, there is a delay in the idle speed resetting to normal. Then sometimes, it "stumbles" afterwards.

I'm thinking it's time for a real good tune up and maybe having the catalytic converter checked out.