won't Idle

I have a 92 Corsica 3.1L that won't idle. It was running fine but had developed a coolant leak. When I took it to the shop, I also asked them to look at an oil leak (not bad). They discovered that it was not leaking oil, the PCV valve was plugged and it was blowing it out. Shop replaced PCV and cleaned EGR valves. Now unit won't idle correctly, It runs fine down the road but stalls when you stop unless you shift it into neutral and raise the RPM. I have cleaned and replaced the Idle Air control, Coolant temp sensor (old one was reading incorrectly) no help. I have a reader and there are no codes and everything appears OK. When the engine is cold and the loop staus is open it will idle rough but will stay running. As soon as it warms up and the loop status changes to closed, it will no longer idle. Any suggestions??

Sounds like the IAC, but let me ask you this. It may sound far fetched but was the idle air control reset properly?I saw a post here a while back from a GM tech that stated many people brought cars in they had worked on and had poor idle problems. After being worked on the car has has to relearn idle etc as all mechanics will unhook battery (supposed to anyway...) when removing sensors or doing motor work. If not done correctly idle will be poor. Since yours won't idle at all that may NOT be the case, but since it started after repairs were made, good place to start. Would check for vaccuum lines broken or loosened during repairs also as I just had a time with poor idle and stalling on my 93 Blazer. Had a major vaccuum leak as a result of a sloppy repair. Check for ANY vaccuum leaks first, then unhook the battery for 4-5 minutes, then restart the car and do NOT give it any gas. let it idle for 10 minutes and see if that helps. May not, but worth a try. That is what he recommended. You might also remove the plate where your AIC goes (if it is multi port) as it will get badly clogged to. I have a 91 Corsica with 170K on it and I clean this and the IAC every year. If the PCV valve was clogged perhaps there is a lot of carbon and such there as well.