My car has the 305 tbi and it has a hesitation around 1200 rpm and so I unhooked the oxygen sensor and it runs the same with a hesitation at 1200 rpm, could this be that my oxygen sensor is bad? I let the car idle until operating temp and the check engne light never came on.

 

I would use a data interface to diagnose the o2 sensor.

First check the IAC passages to be sure they are clean.
Verify good counts.

Check all vac hoses, intake gaskets and throttle shaft for leaks.

 

My thought is that it would seem the issue is elsewhere since unplugging the O2 made no difference.

 

you may think im silly but when I cold start my car there is susshing/loud hissing sound coming from where the throttle body is located but once it warms up the sound goes away but then theres a surging feel during light acceleration.

 

bump for quick replies

 

That sound (probably) comes from IA passage since IAC is controlled to open during cold idle - raising engine idle RPM. As engine warms up IAC slowly closes this passage restricting (reducing) amount of air bypassing throttle plates. On high mileage cars (and trucks) there might be carbon buildup in IAC passage ways.

Leaky TB to intake gasket - could also be the source of your hesitation.

//RF