Misfires and error codes - PLEASE HELP!!!

[bird]

Hi All,

My 2013 Peugeot RCZ (1.6 petrol 156hp, 39,000 miles) has a persistent issue of violent shaking, misfires and the engine repair light. The issue almost feels like a flat tyre when it happens. Of course, the engine repair light comes on as well when this happens. However, this issue only happens under specific conditions...

Most of the time (under town driving and below 65-70mph), the car is fine with no misfires... the engine feel like it runs perfectly!
However, if I drive fast at motorway speeds (particularly uphill) then the issue will ALWAYS happen. In fact, it's so predictable that I can feel the exact moment the misfires build in intensity as the car is put under increasing load.
The only other condition under which the issue has happened has been flooring the throttle in second gear coming out of a roundabout - so I guess sudden intense acceleration.

Some recent error codes
Codes 19th March 2024 - P1340, P1338, P1336
Codes 27th March 2024 - P1340, P1385, P2337

I've done a lot of research on these but many people believe these codes to be relating to cylinder misfires while many others believe these are timing (camshaft and sensor issues).

That leads me to a crossroads as to whether I look at feeling issues or timing issues.

I have done lots of work to the car over the last few months including new spark plugs for all cylinders (Bosch ZR7SI332S) and new ignition coils for all cylinders (NGK 48206) and an oil change. None of this has solved the issue so it seems unlikely to be related to plugs or coils? I've also replaced camshaft and MAP sensors, but this has also had no effect.

SOME MORE DIAGNOSTIC CLUES:

• The ECU suffered some damage after a main battery short circuit 6 months ago, triggering lots of strange error codes. However, this particular misfiring error developed much latter and seems to have really embedded itself in.
• The issue comes on with speeds of 70mph+ and is definitely also related to climbing hills.
• However, driving up short, steep hills with high revs is strangely absolutely fine.
• The issue is not triggered by high revs - it's more related to those long uphill high speed motorway driving.
• I can also feel the car more likely to trigger the misfires if there is a passenger on board adding extra weight to the car.
• The car's idling can go erratic but only if stationary for a long time. For example, if I am in a traffic jam for over 30 mins, the idling might suddenly become erratic and this could then be followed by the misfiring issue when returning to normal driving speed. I've since changed the battery but I also haven't been stuck in traffic since, so I don't know if this is still an issue or not.
• I've tried resetting the ECU by leaving the battery disconnected for many hours but this has made no difference.
• A mechanic reported that a timing code was triggered immediately after they replaced the rocker cover. However, they were not a Peugeot specialist. As such, I don't know if the code that was triggered was actually timing-related or not.
• I have NEVER had the p0087 code which is related to fuel pressure. This makes me think it is not likely to be the high pressure fuel pump?
• The fuel sender unit in the fuel tank is VERY loud indeed. I suspect the car has previously had this replaced to an after market version. It makes a constant loud hissing noise under all driving and idling conditions including the initial pump priming sound when turning the ignition on.
• My breather pipes from the PCV section of the rocker cover and turbo intake pipes are very oily. In fact, if I remove my camshaft position sensor, it is always covered in oil. I've wondered if it could be a PCV issue causing misfires unload load?
• I've had a wheel alignment done so that can be ruled out as the high speed issue.
• The car has no issues starting at all. It starts up perfectly every time and idling is always spot on.... Except for the issue mentioned above if stationary for a very long time.
• The car also has a small oil leak under the passenger side of the engine.
• I've been running an aftermarket turbo intake where the shape of the breather pipe isn't perfect. See photo.

Most of the forum threads I've read seem to point to either the HPFP or the engine timing. However, I've not sure about either...
For the fuel pump, I've never had the p0087 code. And for the engine timing, how could it be driving perfectly when not under excessive load?

I'm pulling my hair out with this so would hugely appreciate any help.

Thanks so much

 

[Charlie1875]

Hi mate, I would change your spark plugs first of all, I’ve had it with numerous Mini Cooper s, same engine, they run fine until you floor the throttle and it can misfire badly, worth a try first of all.

 

[bird]

Hi Charlie, thanks so much for your reply I’ve tried changing them to Bosch ZR7SI332S spark plug plugs and also NGK 48206 ignition coils but unfortunately that doesn’t seem to have made any difference

 

[Verminator]

Sounds like the hpfp is on the way out

 

[Charlie1875]

Agreed, if your spark plugs and coils are good then, HPFP seems to be showing early signs of failure, if you haven’t had it refurbished or replaced, stands a good chance.

usually if the timing is out you would get timing codes eg p0016 stored.

have you access to a decent fault code reader that can check what bar of pressure the hpfp is generating?

 

[Flanners]

stone bonker hpfp.....or at the very least the first thing to check

 

[Pedro]

P1340 camshaft position A bank 1 timing issue ?
P1385 Knock sensor fault or wiring issue?
P2337 PCM detecting knock sensor signal from cylinder 2 over the threshold
Knock sensor faults are usually caused by a misfire-erratic misfires or multiple misfires from timing & fuel air ratio detonation problems
You need to also check the fuel pressures & high & low fuel trims to rule out the pump?