1992 chevy astro van idles ruff and stalls when idoling. Drives fine, idol is no good? Burns oil on one head.?

Ran fine when I bought it. Took it to get smogged, failed smog. Took it to a garage to fix and p it. It ped, but ran different after I got it back. I have to press the gas pedal while starting it to get gas to the injectors. Now the idol has gotten really ruff and it turns off if I don't keep pressing the gas pedal. I was wondering if it just might need a tune up. I bought a book and I'm going to do some reading on it. It seems like it could be a bunch of things. Any chevy guys out there?