Occasional misfire

Hello all,
Please forgive me - I know this has been covered in many other posts, and I feel like I've read them all, but just need a steer on the next stage of a potentially expensive fault-chasing exercise.

Little Suzi (56 M13A vvt) has developed an intermittent misfire, not that noticeable, but clearly apparent when hot, at the lights - stable idle 675 - just a wee shudder. She drives fine, but clearly staggers from takeoff at low revs and has (more than normal) gutless acceleration.
No engine warning light. But noticeably poor fuel consumption

The PCV valve is clear, rattles when shaken, and sucks my finger. Still misfires
I've tried the cold water test on the cam sensor. Still misfires
Unplugging the cam sensor obviously produces P0340. Still misfires

My gut feeling is ignition cables or (pencil) coils now.
Are both front & back coils the same part?
33400-65G01 for M13A VVT

Where's the best price for these?

Welcome to the forum. I would suggest that the idle is a little low at sub 700. I would recommend a good clean of the entire throttle body including the idle control valve. After that I too might look at the coils and leads, ask Martin in the shop on the top banner for a good price. Does it rev clean once it gets going or is it struggling all the way through the range?

Thanks Lambert,

She's always ticked over at that speed when the engine is warm. Like a sewing machine
Revs freely enough, and the miss isn't noticeable higher up the range.
I'll have a look at the throttle body at the weekend. Fixing stuff by cleaning it is always preferable to buying new stuff.
Failing that, I'll ask Martin for his best price - I didn't see coils or leads in the shop - hence my question.

Thanks again

Had it on mine with around 50k on the clock. It's the ignition coils starting to break down. They're subjected to lots of heat where they live and eventually start to act up. It will start to get worse. Sourced some NGK ones of the bay and it's been trouble free since

No eBay APP ID and/or Cert ID defined in Kunena configurationThanks skywalker65,
You are absolutely correct, and at ~55k this was exactly my issue - now resolved
I took a punt on a cheap replacement coil - and used a process of elimination to find the faulty one


She runs perfectly now, but I assume the other (original) coil will also fail eventually.

I'd just like to update this thread for the benefit of others
Occasional "miss" most noticeable at idle, a wee shudder, and less than normal acceleration under power
But otherwise , the engine runs fine and the car is perfectly driveable
No dashboard lights, and no OBD codes.
PCV valve rattles and only lets air through one way
Cam or crank position sensor (plugged in or unplugged) make no difference (apart from the fault light)

Thanks to all on this forum who constantly share their technical knowledge & experience for the benefit of others