I have a 1993 S-10 Blazer and when I put it in gear it either idles real pough and wont move or stalls out..I have changed plugs and EGR valve..Ran fine for 1 day and back to same thing..I am lost PLEASE HELP...lol

 

Check ur iac! I cleaned mine and it helped!

 

Also check the EGR passage for carbon. It can build up in the manifold and flake off and jam the EGR pintle causing a major vacuum leak. If you are having a problem with the carbon flaking off you can put a screened gasket over the EGR passage. I did that with my '93 Sonoma and now it's perfect.