I have a 93 blazer with a 4.3 engine. I've never had many problems with it besides that EGR valve. Recently, when I'm in reverse, sometimes it will just die and I'll shut it off and restart it and it's fine. Then like 2 weeks ago it starts shuddering or hesitating whenever I accelerate. It only does this sometimes, and usually after I've driven it and let it sit and then drive it again. Does anyone know what this could possibly be, it's driving me crazy?!

 

I also have a 93 Blazer that did the same I solved it with new gas filter and two cans at the same time of injector cleaner in thegas tank she has been fine ever since. it worked for me

 

Try some seafoam to clean your system out. It has always worked for me with all my vehicles.