I have an 1992 rs with an tbi 305.The car has sat for about 2 months.The problem is when I try to start it stumbles and die.The car has an new iac,map, and tps.It's firing fine and getting proper amount of fuel.When you remove vacuum line from the rear of the throttle body it runs good for abuot 10 seconds then stumble and die.IF you unplug the tps and remove the vacuum line at the rear of the throttle body the car starts and idle normal.It will run until I cut it off or try to give it some gas.I forgot to mention car also has new fuel filter and fresh gas.Currently at a loss any help would be great thanks.

 

Check TPS voltage and coolant temp sensor (the one for the ECM), MAP sensor and especially the vacuum line for the MAP sensor. A scanner would really come in handy if you have access to one.