I have a b2600i, pulling each plug wire causes no change to r.p.m. on cylinders 3 and 4. 150 lbs. compression all cylinders. New fuel filter, plugs, wires, rotor and cap.

Not noticeably. Since the injectors fire in pairs, 1 and 3, 2 and 4, I pulled all injectors, figuring two (3 & 4) were bad. Hooked an electric fuel pump to each injector in turn, pumping injector cleaner through them, when power was applied to the injector terminals. With the coil lead disconnected, all fired while secured into the fuel rail and fuel pump hose attached, off the engine, with the pigtail attached to each and plugged into wiring harness, while spinning the engine. Now no start, have spark, plugs wet.