Checking the Engine Ground:
If anyone has <any> kind of problem with hesitation around 2700 rpm, running rich, lack of power, having trouble getting hp out of higher rpm's or unstable idle (shaking) READ THIS:
Today I decided that my '92 SE was ticking me off with this hesitation problem. I decided to proceed and check ALL the wiring going to the ECU <Not an easy task>
Anyway, I had my car to the dealer about 3 times and they didn't find a thing. I finally checked the grounding (Battery to chasiss) and the meter read 34 ohms. This should be 0 ohms so I made a jumper out of 8ga amplifier wire and grounded it to the chasiss. I also repaced the braided wire towards the back of the engine grounding it to the firewall. I took the car for a spin and it drove like an infinity and had the accelleration of a 300zx (seemingly). Needless to say this fixed all the problems I have been having.
To check yours:
Aquire an Ohm meter
Place one probe on the batterys negative terminal.
Place the other probe to any other un-painted screw on the body of the car.
Make sure resistance is under 2 ohms
Hope this helps! Worked for me and fixed all my problems.