I have 93 gt with: f cam, holley systemax intake, 70mm tb, 73mm maf with 19lb sample tube. The car will idle fine for about 3 minutes then will start to rev up and down, and dies. I tried adjusting idle between 700-900 rpm with the same result, my base timing is at 12* Where should I go from here? Thanks

 

Just taking a wild guess, but the IAC might be the issue. You can get one these to help set the idle and hopefully resolve that surging issue...

idle air control adjuster - LRS Search

 

I have that adjuster, and it does absolutely nothing. the only way i can adjust idle is with throttle plate stop screw

 

sounds like a vacuum problem

 

With the car off, disconnect the IAC, start the car, set the idle, then plug it back in. If that doesn't help with the idle, then yea, that isn't the issue. When I had issues with the IAC, that was the only thing that cleared it up.

On your MAF, is the sample tub on the top side? I have seen that cause issues as well.

 

My car did the same thing I just removed the iac and built a delete plate, then set idle with the set screw.