I have the hesitation problem in the 3800-4000 rpm range I cleaned the grounds checked the fuel filter and it is still happening it is so bad that the car stalls out if I keep my foot on the throtle. Any help Please!!!

 

http://www.fc3spro.com/TECH/FAQ/3800.html

 

If you do a search on grounding the ecu there is a thread with pics which shows how to add a ground to the ecu within the car as opposed to removing parts of the engine to check and or fix the problem.

This link should help:

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/ecu-ground-wire-questions-658615/