I have a bad problem with my car hesitating and stuttering really bad when I accelerate and the car has gotten really slow. The problem has steadily gotten worse.

I have a 90 teg so the PCM under the carpet is where I get the trouble codes from. When I turn the key to on (I also have the jumper wire installed on the plug on the ECU) the light blinks once fast and doesn't blink anymore. My question is: Is this a flash showing that the PCM is working or is this an actual trouble code?