1993 toyota carina e performance and electrical issues

the image below is a device that came with my 1993 toyota carina e. my 1993 toyota carina e uses petrol and LPG gas but the LPG gas section has been deleted and it came with Engine ECU and the device in the picture below. please i want to know it name and functions. when car can't reach 120 km/h it can go again and sometimes it will take long time before it reach 120 km/h. i disconnected the connection to the device in the picture and now my fuel gauge is not working. advice please should i keep the two or delete the connection to the device in the picture. thank you

Tracing information on old LPG conversion kits can be difficult if not impossible. I don't recognise what type of LPG ECU that is but I am guessing the car had an old style LPG carburettor.

With that type of system the only parts of the cars' systems that are cut and joined are normal the fuel injector wires and sometimes the fuel pump and in this case the fuel gauge. To remove the conversion it is simply a case of finding where the wires have been cut and spicing the original wiring back together. In this case I suspect the longterm fuel trims will have been knocked out of range and a battery disconnect to reboot the engine computer may help.

However if the car is severely down on power I would suspect a issue with the engine that needs properly diagnosed - perhaps a blocked catalyst.