AGU 1.8T misfire

[manwithtool]

The car developed a misfire immediately after I nearly stalled.  I've had the car 2 years and  hadn't replaced the plugs.  So changed the plugs and no difference.  I had a spare set of coils so fitted one no differnce...moved the removed one on to next cyl and so on.  Still 1 misfire.  Swapped all coil packs, no difference.  unplugged Cyl1 nr timing belt and the engine note didn't change so No1 has the misfire.  disconnected the other plug one by one to ensure no other issues.  So misfire is Cyl 1 so swapped coil packs a few times even with Cyl adjacent. Still Cyl 1 misfire.  Plug did smell of fuel so I think it's ign problem   I hav't swapped plug to different cyl yet.  They are the NGK Platignum plugs.  Anything else I can check ? I think the 3 wires going to the coil are pos neg and signal.  Can I test the pos and neg feed ? and if so which are they.

Anything else I can do ?

[Adam54]

Hi,

A common issue with this engine is the ICM or Ignition Control Module.  It is a small black unit fitted to the air filter box. It is actually an ignition amplifier unit, with 4 power transistors within.  Judging from other comments online, the transistor legs become detached over time (more commonly cylinder 3), leading to a persistent misfire.  On my car, this did not lead to any codes in the Onboard diagnostic port.  Access is easy and a replacement cost me £25.

Good luck.

[manwithtool]

Hi Adam,

yes you are correct.  It was next on my list and it cured the problem.

Thanks 

[Adam54]

Glad you got to the bottom of it. Very satisfying to not have bought 4 coil packs, new wiring loom, MAF etc trying to nail down the problem.

Cheers,