Hesitation, missfire?
 

Hi All,

My 2.5 STI 56 keeps repeatig a fault of hesitating, holding back like a missfire at about 2000rpm and up.
No check lamps at all.
I checked the plug gaps, conditions etc, all ok.
I cleaned the K&N air filter which was dirty and re-set the ECU via ECUexplorer and it was fine. A week later and its doing the same thing agin.
I disconnected the MAF and the engine drops its idle and brings the check lamp on, reconnect it and the engine stops. Check light stays on until ECU reset.
Car is standard apart from backbox and center resinator pipe.
Any ideas?

coil packs

Short of buying one and swaping them out, one at once, any way of checking them?