One of my throttle body screw holes is slightly stipped. Should I use a tap to rethread it? Will I need a larger bolt? is there a better way?

I have a vacume leak(I assume. Get a high idle after warming up) that I cant track down.

 

what year?which screw holes?

 

heli coil and shop vac.

 

1990. It's the one on the back passenger side.

 

Replace it with a stud and JB Weld it in.

 

One of the 3 mounting holes on the intake manifold?

 

No not on the intake manifold. On top, the air inlet tube from the air box

 

I think you can tap it to 1/4-20 and use that size bolt. Pretty sure one of my old XJs had that done when I got it.