84 century

I have a 1984 century 1.9 liter six cylinder. I have a unusual problem. If I am driving the car forward it is fine until I stop. If I stop a little fast the check engine light comes on. If I am going forward and drive over a slow bumpy road and make the car go up and down the check engine light comes on.
But does not die unless I stop real hard.
If I put the car in reverse the light comes on hard and the engine dies. If I put the car in reverse and then put it back in park before the engine dies the RPMS go up tremendously. Like someone dumped a whole bunch of fuel into the carb. Anyway I took it too a quasi dealer. They service many brands. They didn't have a service manual. At first they thought it was the knock sensor. Then they thought it was wiring. i.e. put the car in reverse and it torques the engine. I did not want to pay 600 dollars for them to go through the wiring harness. I work on electrical products. Anyway I went through the wiring with a fine tooth comb. Could not get a check engine light no matter how I yanked on wiring harness's. I am convinced it is not the wiring.

But for some reason they felt it was maybe the knock sensor. I think I have located the knock sensor and I read on the internet that knock sensor are pizoelectric and put out a frequency. Does the knock sensor normally put out a 0 volt signal. In other words could I just disconnect the knock sensor and ground the signal going to the computer to see if the symptoms in reverse go away.

I keep thinking it has to be related to the transmission because it is so bad in reverse.
Is there a way to get the engine codes without a computer?
Sorry for the long winded post.
Any input will be appreciated
Thank You