92 tc stumbling engine

the other day my car out of nowhere stumbled, like no response to throttle pop and die. i think bad gas was to blame. i put a can of seafoam in the gastank to remove moisture from the gas, and then i let it sit all afternoon and over night and it started and worked fine for 2 days. then this morning at a stop light i hit the gas and it went foward but it was like i had no power and it felt like it was trying to pump the gas pedal. then at the next light it just died. i started it up and then it ran with no problems until i got to school about 6-7 miles away. it seems like it only does it when the car is at idle. and it seems like when the engine rpm drop to idle it runs rough for a second or 2. so know i am thinking that the vacuum lines have dirt in them causing the rpms to drop to low at idle causing it to stumble when you hit the gas. what do yall think.