1988 Dodge Omni Stalls at Stop lights

My vehicle very recently has started to stall at stop lights, and signs, once or twice as I go around a corner at slow speed. If the car stalls it used to start right back up, now if it stalls it is more difficult to start up. I have recently replaced the pcv valve and all of the tubes that lead from the carberator to the valve and the elbow from that cam cover to the pcv valve- the tubes were brittle and broke when I was trying to check the valve. It seems to work better when it hasn't been used for the weekend, or if it is started ahead of time and let to "warm up". I was told by a mechanic to use carborater/fuel injector cleaner in my gas tank and to clean the carorator my self. Other problems with the car (listed in case they might help dtermine the probelm.) I have an oil leak coming from the oil pan seal, the exhaust is broken before it reaches the muffler but is patched more or less sufficiently. If there is a good likely hood for the culprit or even a good method in which to check the vehicle any advice would be greatly appreciated.