have pumped $ in my ford can you help?

I have a 1993 ford explorer xlt w/ 6 cyl it has 110k mi. Extremely rough idle have changed mass air sensor, throttle position switch, feul idle regulater, and feul pump with filter no help. Runs better when disconect air tube from throttle body.Check the intake air sensor its 0 ohms the haynes book says it should read higher is the sensor bad?