I have a 95 blazer that had a bad EGR valve. i have repaced it but it is stuttering when i first start driving up to 30mph, then it smoothes out. Every once in a while it backfires. I have put fuel- injection cleaner in it twice. I have know clue what is going any help would be greatly appreciated. The tachometer also keeps bouncing back and forth. i dont know whats going on with that either.

 

I would start with a fuel pressure & leak down test. The CPI fuel system is known to have its share of problems.