Have taken off the fuel injectors from a ford 4.0 doing work on the engine,would like to if there is a way to test each injector off the car maybe with a multimeter or some other gauge to see if there in good shape Thanks

Was getting 17 to 19 mpg. Suddenly dropped to 13 mpg but run well. New plugs, wires, coil pack because developed miss-fire on 2 & 5 but this was after the problem started. I have been putting Sea foam & lucas injector cleaner in for 3 tanks. Seams to do slightly better but at idle on these cold mornings fuel consumtion is terrible. While I am waiting for my heavy equipment to warm up fuel average will drop in 30 mins from average 18 mpg to 12 mpg or lower? Any suggestions? I am very much mechanicly inclined, 2 race car's, 160 personal autos, rebuilt many engines etc. Got me and my buddy, 1st class mech w/ 31 years exp stumped. also, have problem w/ atc varying constantly, w/ max air only in summer. The black box behind the console control, does that control atc temp adjust. Thanks Mac