ttt

Random???????

like not next to each other, it has compresion and is getting spark, SOMEthing has shut down 4 cylinders and there are no codes, I don't know what else to say

OK lets look at what we have please correct anything I don't get right .......random cyl not firing but all have spark I take it you checked the firing order, all have compression over 100psi, none are next to each other,
I would have to check the injectors with a noid light and make sure they are getting a signal then check that they are getting the right signal, then id try changing them with known good injectors...pretty much short of a bad computer it has to be injector or spark related please let me know how you make out!!!! and good luck

liquid,
Any progress on this? Joe seems to agree with me that the signal (power on and off) at each injector should be checked. Each injector driver (there are only two) triggers four injectors, the middle two cylinders on one side of the engine, and the front and back cylinders on the other side. But it would always be the same four cylinders, it would not jump around as you said.

Your problem is a strange one. One thing that I don't think has been mentioned, but that can cause unpredictable problems, is secondary ignition voltage inducted into the knock sensor or ignition control citrcuits. In other words, make sure that the wires that go to the knock sensors and the wires that go to the distributor are not resting against any spark plug wires or coil wire. Its a long shot, but thought I would mention it.

Dave

I got similar problem happening to mine now . Did we ever get his solution

Yeah, redo heads, valves,injectors,fuel pump, water pump,

not all that had to do with the prob, but all that crap broke in the mean time, fixed it all right and sold it