First thing , check voltage wire 29 on circuit board that is your potentiometer wire it should be around 3. 5 volts as you push accelerator it will will drop to less than 1 volt if it doesn't drop below 1 volt 1 a or bypass will not engage
2- check voltage at T-2 that will tell you if you have a bad #1 rec also test the shunt if it has dark marking it could be faulty with your symptoms I would also suggest to test drive motor also look at the thermal protector it will have two wires a black and gray I also had issues with plug on card unplug z plug look at pins make sure they are all in tightly and plug back in and put a piece of cardboard between lock and plastic base that keeps plug tight in card if forward and reverse come in then it isn't switches or safety switches ie brake etc it is a control issue the symptoms you describe is more common with rectifier, shunt , control card , motor , thermal protector or fuse