Clyinders 5+6 B misfire

[rajinder_1]

Hi guys,
Have just been out in car and noticed the engine management light come on and it was real lumpy and poor respose to accelaration.....
I had a friend who ran diagnostics on the car and found that Cylinders 5+6 were misfiring on B. He changed the leads over and swapped the coil pack for a new one both with no joy.
We (well he) ran a test on the MAF and that was showing ok i think it read 16 which is ok on the M112 engine ( needs to be between 12-20 i think ).
He reccomended changing the plugs as this was the only thing left, now im not to sure as i would need to replace all of the plugs and according to the servoce these were only change around 1-2 yrs ago (from what i recall).
Has anyone had any problems like this with a similar fault does anyone know what could cause this?????

Regards,

Raj