surging 02 zetec

[focused83]

Hi,
I have an 02 focus zetec that has been surging on hard acceleration and when accelerating out of low revs from any gear, and is more evident when the car is hot than cold. Driving like a grandma the car is ok, but i do not have any power to take off when i need to or overtake vehicles etc like i should.

A private mechanic replaced the spark plugs which fixed the problem for a few weeks. When the problem started up again I went to Geraldton Ford (WA) hoping their diagnostic equipment would be able to find the real source of the problem. On each of my 4 visits back to Geraldton Ford they have cleaned the throttle body, gaped the spark plugs (at this time were only a few months old and already burnt out), replaced the fuel filter which they found the ford mechanic (now dismissed) had not previously replaced on the 60,000km service, replaced the battery and added solution to the fuel tank to absorb any moisture. The problem was still evident. I then took the car to Rockingham Holden (WA) who claimed it was the coil pack needed replacing (they also said the spark plugs and cables are fine and the diagnostics are not pointing to anything in particular to be wrong with the car). This also fixed the problem for a few kms, however when the car warmed up the surging has started to return. A friend suggested that the injectors may be dirty but the vehicle has only ever had 98 or 95 octane fuel. Has anyone had a surging problem like this? Any suggestions?