1995 Blazer Idle and Starting Problem

My 1995 Blazer 4X4 (4.3L V6) has been idling rough and is sometimes hard to start. It seems to happen after the engine has been running for a while. First start in the morning is usually very easy. However, after being warm for a few hours it will start to idle rough. And when I shut off the engine then go to restart it later, it sometimes takes several cranks, lopes to a start and idles really rough. There's no problem with acceleration and engine performance is generally very good at speed. I took it into my regular mechanic. He checked the fuel pressure regulator and said everything looked great. Since he had it first thing in the morning we couldn't seem to get it to "act up." About three months ago he replaced the throttle position sensor. I've kept up on all regular maintenance including fuel filter, PCV and so on. It almost feels like a vacuum leak somewhere. Anyone have any ideas. By-the way. The vehicle has 145k miles and I've had relatively good luck since buying it brand new. Thanks.

Do a search for CPI injector in this forum.

That is your problem.