I've recently developed a misfire from 3500 rpm onwards.. The car runs absolutely fine at idle and in all gears up to 3500 rpm.
At first I thought it was a bad batch of fuel (Momentum 99) but I've ruled that out due to the misfire only under load. I've got a Evoms intake, R8 coil pack and new spark plugs on order so hopefully this will resolve the issue.
There is no EML on and I have scanned using an obd2 scanner via Torque. It's booked in at a garage for a VCDS scan but if anyone has had similar issues or can offer advice it would be appreciated.
Cheers,
I take it there weren't any codes stored when you scanned it with Torque? Definitely get it scanned with VCDS, it's half the battle won.
Ideally you'd get a code showing a misfire on a specific cylinder, say cylinder 2. Then swap the plug on 2 with the plug on 3. Clear the codes. Get it to misfire again. Scan. If the misfire has moved to cylinder 3 it's therefore almost certainly a bad plug.
If the misfire stays on cylinder 2, do the same thing but with the coils. Swap coils 2 & 3 over, clear codes, misfire, scan, misfire on 3 points to a bad coil.
If it still stays on cylinder 2 after you've done all that, it could point to a bad injector, or a mechanical fault with the engine itself. A compression test will help.
I went through all of this and got as far as concluding it was likely to be a bad injector causing my misfires. I bought a used set off a breaker which I had refurbed by mrinjector. Seems to have done the trick. You might just be able to bang a single used injector in and fix the misfire; I figured a refurbed set of 4 made more sense to me.
Hopefully it's only a coil or plug causing your misfire though. That's much cheaper than injectors or worse. Make sure you try swapping things round before you fit any new parts - you'll know where the issue lies doing it that way. You could just fit four new plugs and four new coils but you wouldn't know exactly what failed and what you're fixing.
