I have tried the corsa forum,

Basically, guy put diesel in it, only a gallon, before setting off from petrol station, filled it up with petrol to dilute it. Then drove the 7 miles home fine.

Then drained tank and refilled with petrol. He said it ran rough. So i bought it back. Drove it for nearly a week without a problem.

About 4 days ago, the car seemed to drop onto 2 cylinders and fluctuating idle from 500-1000RPM.

Ive changed plugs, coil, leads, Engine loom, map sensor, TPS is working fine as tested using my snap on scanner.

No codes are present,

It is PERFECT when cold, it varies on when it plays up but can be anywhere between 2 and 5 miles from starting when cold.

What could it be?

Exhaust backbox blocked? (No middle box but wouldnt it cause a loss in power all the time?),
Fuel Filter?
Injectors (But wouldnt it cause a problem all the time?)

Im really getting narked off with this now,