M52 misfire under load

[Ch4ni]

Hi I competed the M52 swap last year, it has been running fine, recently the engine starting to misfire under acceleration. From cold the engine starts up fine, runs normal no misfire under acceleration, gets up to normal temp . When the engine has been running for around 30min, when the in gear and under acceleration the engines begins to misfire and sometimes back fires. The engine idles and revs fine when in neutral with no misfire, it only happens when under load.

Is anyone able to advise what could be the issue?

[Brianmoooore]

Coil packs are a known weak point on these engines. It's not a 'wear' thing, so only need to replace the faulty one.

[Ch4ni]

Coil packs are a known weak point on these engines. It's not a 'wear' thing, so only need to replace the faulty one.

Thanks for the advise, I will check the fault codes for coil pack failure and replace them over the weekend and report back.

[martauto]

Coil packs are a known weak point on these engines. It's not a 'wear' thing, so only need to replace the faulty one.

Thanks for the advise, I will check the fault codes for coil pack failure and replace them over the weekend and report back.

Speaking through experience on my m54 dont buy cheap stuff, it will only bite you back harder.

Mart.

[Ch4ni]

I checked the DME for error codes and the only error showing is "34 solenoid vale, exhaust flap". What this refer to? Do i need to do anything for this error? I guess this is the exhaust flap in the exhaust which I don't have now.

I ran the car at the weekend and it was running fine, I will have to monitor to see if this issue re-emerges

[martauto]

Does it smoke a lot/bit or now and then ?
The CCV system (crank case ventilation ) is a big culprit for the engine running like shit/misfire etc.
Bosch coil packs and a new CCV system transformed my car into a "pleasure to drive " car.

Mart.

[Ch4ni]

Does it smoke a lot/bit or now and then ?
The CCV system (crank case ventilation ) is a big culprit for the engine running like shit/misfire etc.
Bosch coil packs and a new CCV system transformed my car into a "pleasure to drive " car.

Mart.

Hi Mart, the engine does not smoke at all, The misfire only happened after it had been running for around 30mins, I will need to monitor if this happens again and note what faults codes come up when it happens again.

[martauto]

Mine used to misfire when warmed up and finally bit the bullet and put Bosch coils on which did the trick.
The codes were totally crap and told me all sorts of rubbish which could have cost me lot`s in sensors but my mechanic said it wasn`t so and he was right.
The smoking ,due to the ccv system started just before and carried on for a few weeks until it became really embarasing .
I had a breakdown company out to her just weeks after I bought her and he said "head gasket" straight away based on the fact the oil filler cap was clean but the oil and water were fine.

Mart.

[Ch4ni]

What I have noticed is that when it starts to misfire when it up to temp, I can smell a lot of fuel, it looks like its running rich what could be causing this, vacuum leaks?