Bad idle, acceleration, smoke in exhaust

[Fett32]

So my car has been idling badly for a while, like a bad IAC, and it then started to run bad at speed. It would stumble on takeoff, and the gas would seem to cut in and out. I have replaced the coil, spark plug wires, spark plug, IAC, throttle position sensor, PVC valve, engine and tranny oil. Recently, it started to billow black gas out the exhaust once in a while, and I had to take out the cadillac converter because it got clogged. Today, I tested the resistance on the injectors. 3 of them were about 13, but one was 33, so I went over and replaced injector.

Afterwards, the black gas stopped, and it was replaced by an almost constant white gas. Usually while driving the engine strains and white gas comes out. Once in a while it will run fine, idle, acceleration, and at speed, but its usually running terribly. It then also developed an occasional backfire, along with a nice big cloud of black smoke. It also still does the horrible acceleration, with the gas seeming to cut in and out, and the engine almost dying and then revving up to speed, then almost dying, etc.

Any ideas greatly appreciated, the way it behaves I'm thinking there is just a couple small things I can't find that is causing the ECU to have trouble running properly.

[Sheppyman21402]

Is there a air line that isn't attached right? Or even the MAF sensor isn't tight on the tubing? I can't explain the smoke or clouds. All i can think of was the CAT which you swapped and the MAF... Mine was loose and it ran like garbage. check the whole intake system for leaks...

[94legacy22]

these are known for bad knock sensors, look at it, if its cracked replace it.