Hi guys. I have a 96 Ed falcon. Bought with 129,000 ks on the clock. It misses in a very strange way.
Starts perfect but when mainly cold or ten mins after starting the idle plays up the revs go from idle down and up from almost dying to idle. I feel the engine compensating and the car trying jumping forward a little then back to idle. Under very light throttle it misses and the revs die right down and it putts along and after 5 seconds or so it picks up. Happens mainly at lower revs. If I put the accelerator down hard it jumps forward and takes off. If I hold the revs at a setts in point and hold it the revs fluctuate from say 2000 rpm down to idle and back up. U can hear it spluttering and dirt of missing. Worse on cold morning and is better when the car is warm or the temp outside is warmer. But the fluctuating revs is always there the miss under load is mainly when engine or outside is cooler. Twice in the 3 years I owns it it has died at idle and once it felt like the engine cut out completely for a second. The clock is at 171,000 ks now and the engine has never changed how it runs in that time.
I replaced leads, plugs, coilpack, computer, throttle body, injectors, fuel filter and air filter but no change. A machanic once tested it told me injectors as nothing electrical was wrong. Injectors did not fix. Any ideas?

Headgasket? Can cause misfire across the rev range. Incorrect plugs

Head gasket. It dies not lose any water in the four years I owned it. Never loses oil. I don't see how it can be head gasket. It's done it for 4 years never changed.

New mechanic for a start.
Have you thought about changing the inlet manifold gasket, cleaning the ISC and making sure it's gasket is ok.
Looking for other vaccume leaks.

I have looked for vaccume leaks. I can't find any myself. Have not changed the inlet manifold gasket.
What is the isc?

Idle speed controller, do a quick search on how to locate/ clean it.
Does it use alot of fuel?

I bought a second hand throttle body and put the throttle position sensor and idle control on and it wouldn't idle. Did the same thing as it did before so I put my old idle controller back on and it idled again. Still the same. Will the idle control make it surge through certain rev ranges? Fuel usage I get 750 ks a tank. I bought a crankshaft position sensor you think it may be that? I'm still waiting for it in the mail you think it might be that? It surges or misses in certain revs. At idle when it's cold and when I accelerate slow the revs stop at 2500 rpm and it sort of gets stuck and then jumps forward and gets all this power. If I put my foot down the power fluctuates ??

timming or fuel pump?

have u looked at the harmolic balancer?

First question I have is, what model car do you have? An ED or and EF. You say you have a 96 ED. ED is 94 and EF 94 to 96. It will make a difference to what you are trying to fix.

In the op he writes a list of items replaced, note coil packs.....

I thought the 96 ef was timed automatically and the sensor that replaces the dizzy is the only way to fix it?
What does the harmonic balancer do with a miss fire?

Sorry it's a 96 ef.

If it is breaking down under load, I would have said either Leads, Plugs of CoilPack, but you said you have done these. Could be blocked injectors or a blocked fuel filter.

I done injectors to. I got a crankshaft Angie sensor in the mail?. It's breaking under load sometimes at idle when it's cold it's like it's running out of fuel. When it's under load it like one piston stops firing and it lacks power and skips then comes good. It won't hold a steady rev it fluctuats up and down. If I hold it in neutral at 2300 rpm and hold it there the revs by its self goes down to 1000 rpm then starts missing then goes back up to 2300 then may even go up to 2500rpm and so on. It's been doing it for 4 years. Never changed. It's just done my head in now.