Truck Forums - No power in chevy truck

I have a 1990 Chevy 4X4 pickup 350throttle body injected engine, auto trans. The truck has only 119k. miles, sits most of the time. I have a couple problems that have persisted for a long time. It has no power, especially when pulling a trailer and uses a lot of gas. I have changed everything electrical as far as plugs , wires,high output coil, and the ecm in the distributer. It seems like it is getting too much fuel. Wheni wouldtake the air cleaner off and look at the injectors when it is running, there was a very strong stream of fuel coming out of each injector at idle speed. I changed the engine coolant temp sensortoday and it seemed to cut that flow down some but i don't think it helped enough for pulling a trailer. Could it be a problem with the fuel pressure regulator or injectors ? Second problem with the same truck is the back brakes never worked. Don't even wear brake shoes on the rear in seven years. The brake dash light constantly flashes nine short flashes followed by one long flash. And sometimes when I get out of the truck ,I notice that the rear brake lights in the tail lights are sticking on, until i go inside and pull the pedal up to shut them off. It seems to me like proportioning valve is not working but it also has a couple electrical components beside the master cylinder for the anti lock brakes. I hate to just start replacing everything. Any help would be appreciated.