Where is the best spot for a ground on the car?
I want to ground my black pressure sensor ground to stop my hesitation

 

That would be the lug where the negative from the battery terminates at the starter.

 

The battery....

Seriously, the starter is good. Or the bolt on the driver's side strut tower where the ground wire from the battery is attached.

Chris

 

wheres the black pressure sensor on a 1988 rx7 SE n/a???

 

If your new ground for the sensor does not work and you also make better grounds at the ECU, you might take a look at the secondary injector plug wires. Both of those on my N/A had been burnt in a fire and new ones had been spliced it to the harness. The spliced wiring was, how shall I put this, not done quite right,(previous owner or course) and caused periodic stumbling when the pedal was put to the floor. If none of that works you might try another pair of secondary injectors. If you have the time, you might see if swapping the primary with the secondary injectors gives a different scenario. If it does maybe it is the secondary injectors. Seems if you did this the stumble would happen at a different rpm etc.
Crossbar, here is a picture http://home.earthlink.net/~burntoast/ well actually here http://home.earthlink.net/~burntoast/images/rx7/maf.jpg Oh by the way. On the turbo the manual calls it a pressure sensor and in the NA section they call it a boost sensor. At least in my manual. Screwed up people.