i have a 1987 blazer 4x4 it starts to chug between 25-35 mphwhen slowing down and speeding up(just in that range of speed)i have chaned plugs,plug wires, oil change, air filter the only other thing i could think off would be fuel filters or sensors any other opinions?

 

the egr valves seem to be a common problem, wouldnt hurt to clean yours, if i knew how to add a link to help i would, but a liitle searching you could find the thread.

 

i'll try it thanks!

 

I had a similar problem and for me it was the Computer went bad. If you can get a computer scan that would help. also try checking your 02 sensor.
-Wes-