My 1995 2WD Blazer just started idling horrible right after starting only, then it levels off smooth. Sometimes the idle revs up and down, sometimes the idle is all over the place. And the whole engine has bucked a few times immediately after starting. Sounds like something's going to break in there. Like something is out of tune in the engine. Anyone know what causes this?

 

You might have excessive fuel leakdown going on causing an excessively rich condition on start up. 1995 was a split year, there were two completely different types of injection systems used and the diagnostics are different. Which system do you have?

CMFI:



Or CSFI:

 

possibly also a stuck open EGR... this was my issue last week. Carbon had fouled the EGR causing it to stick wide open so my motor was seeing a HUGE vacuum leak.