Oldsmobile/Buick Repair: hard starting/ engine stalling, vacuum leaks, buick skylark

Question
1990 buick skylark 4 cyl.no over head cam/throttle body injection/automatic/air.
I did a tune up plugs,wires, pcv ,air filter,changed oil.Recently it started to stall out when I am comeing to a light and have to stop.And at times it won't start.But after leaveing it sit for 15 minutes it will start.
I have added new fuel and ran a tank of fuel with a can of dry gas.There seems to be a little slack in cable [throttle].Is there a way to turn up the Idle? Can I turn [advance the timing ?Or is all this controlled by the computer?I used to tinker with the cars of the 60's and 70's but this is my son's car and we are both strapped for cash.Any advice would be greatly apptrciated.     Thank you /happy holidays
                The Wheeler Clan  

Answer
Hi Mike,
Vacuum leaks is where I would check, and be sure to include the EGR valve in the cleaning. It will act like a major vacuum leak if sticking open.
There shouldn't be slack in the throttle cable, so check the mounting areas of it.
Next time it won't start, remove the gas cap, and see if it is forming a vacuum in the tank.

Van