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Discussion Starter #1
I've been experiencing an intermittent misfire of sorts for the past few months now, but as the car has only just come back from its winter break I want to get it sorted.

It only ever happens at high revs, just as I'm about to change gear at full chat between 1st-2nd or 2nd-3rd.

It feels like the ECU is cutting power as I get the MCSF on the dash which instantly resets itself and usually the ASR turns itself back on.

I've tried checking for fault codes but haven't got any showing on my limited diagnostic OBD reader.

It's very noticeable in exhaust/engine noise too. Can be quite embarrassing too as it sounds like I've missed a gear!

Any ideas?
 

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I'm assuming you're running a wizard exhaust? (Car throttle) Have you deleted the cats?

Some of the symptoms you describe could be attributed to lambdas failing - I had a fluffy throttle for quite some time and it was only when I changed them that found I could heal and toe again. But also, I'd suspect crumbling wiring to the injectors and coil packs. The coils themselves could be failing.

However, given that you're up-changing and the ASR is involved, it could be also be an ECU issue. As in the capacitor that feeds the TB - a known issue.

Might be worth checking the earth point I identified in this thread;

https://www.alfaowner.com/Forum/alfa-gta/1176883-156-net-saved-post-alfa-147-andamp-gt-p1688-fault.html
 

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Is the fuel pipe that connects your two injector rails still original? Or has it been replaced?

Manifold cats have been replaced for decat manifolds on this car, it does still have the secondary cats, but even so a low cat efficiency error won't make the car run any differently.

Is the air mass meter original? Does it stay misfiring for long?
 

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Discussion Starter #5
As far as I know, the air flow meter is original (nothing in the paperwork to say otherwise). Same goes for the fuel pipe.

The misfire clears itself as quickly as it comes.

The plastic trunking around the wiring that feeds the coils has seen better days, and could probably do with the engine loom having a going over really.

My first suspicion was a faulty coil but hard to tell. It's going for a visit to Ned in the next couple of weeks so it can have a proper going over. Unfortunately as the error clears itself straight away and is intermittent, I've no idea what to expect.

Hopefully something simple and not an expensive bill...
 
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