Iv got a strange intermittent missfire on my 2wd saph that iv had for months and months and im really gettin pissed off with it, i dont get the problem every time I drive it I'd say it happen 8 out of 10 times but some times it don't happen for days and weather conditions don't make any differance, the problem is when I accelerate up to and pass 4k revs the car really pulls back and feels like iv hit a brick wall and gives a nice loud back fire and some times kicks out a flame but anything under 4k and you wouldn't dcdn know there is a problem. Iv tried changing the normaly things but I'm getting no where, has anyone got any ideas on what it could be or what I should look at next?

Iv searched through loads of old posts with similar problems but none of them had posted the cure just the problem.

Things iv changed,
Plugs*
Leads
Dizzy & arm
Phase sensor
Grp a Coil*
Engine coolant temp sensor
044 pump
Fuel pressure reg
Injectors (greens)
Fuel pump rewire

Any help would be great thanks **
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