I just bought (8/13/2011) a 1994 Blazer k1500 with the 5.7L TBI injection, auto.......189k on her!! She runs good beside this Idling issue....

If I let it idle longer than 60 seconds it will die.

If I sit at a signal it will die, sometimes no ( but getting worse). Once on the road , no problem. If I give it a little gas ( like in a parking lot) and let off....it starts to get a loppy idle like it has a cam....and then I can feather the pedal to make it go away.
I have read on other forums and I am looking at a MAP sensor, an IAC?
I pulled a 42 code from the flashing "service engine" light?
Any help would be appreciated.!!!
This is one of many little issues. It also has an A/C problem.

 

42 is ELECTRONIC SPARK TIMING (EST) CIRCUIT

Not sure on what to think,check and see if the timing wire is unplugged. With it being a 5.7,i dont know if its in the same location as my 91 1500 was,but it was on the firewall behind the engine on the left side. It plugs into a connector on the wall. tan wire.

 

I have resolved the idle issue. I replaced my idle control valve, took it out for a test drive and I could not get it to stall. I still get a little hesitation, but a tune up is coming and I hope this will resolve the issue......BUT IT DOESNT STALL NOW!!!!! Woooo..hooooo......How do I clear the "service engine soon" lamp? I am looking in the forums for it right now...