93 shadow rough idle

my 93 shadow ildes very rough. sometimes sitting in traffic it will shut off. i have replaced plugs,wires distributor cap and rotor,fuel fiter and sparkplugs. also looked for vacuum leaks(found none)while reading the plugs it appeared that two cylinders weren't firing. i was told possible fuel injection problem. how can i test the injectors? and any other ideas would be greatly appreciated.

scott

easiest way to test the injectors is to get a screwdriver, put the handle to your ear and the tip of the screwdriver on the injectors and hear for a clicking sound. If you have the 2.5 liter, remove the air cleaner and put it on top of the injector and hear for the clicking sound.

also, as a side note, if you have two plugs that appear to be not firing, with this particular engine, the 2.5, all the cylinders would be missing because there's only one injector on this engine. Do a compression test on those cylinders that appeared to be dead. You can also do a cylinder power balance test best getting some vacuum hose, attaching it to the terminals on the distributor cap, getting a small jumper wire (the gauge of the wire can be 14 gauge) and a screwdriver. Attach one clip of the jumper wire to a good engine ground and the other clip on the jumper wire to the screwdriver. With the tip of the screwdriver, touch the vacuum hose on the distributor cap (make sure you reattach the spark plug wire to the vacuum hose). If the engine runs better, that tells you that you have a weak cylinder.