Bogging/misfire under load at 2-3k

[KaitlinE07]

Looking for advice if possible, my 197 always bogs out/misfires between 2-3k revs under load, slow acceleration seems to be okay. Doesn’t show anything when it’s plugged in and I’ve been told the map is sound, wondering if anyones experienced this or has any idea where to start?
TIA

 

[Usman]

This happened to me when I had my 197. Turned out to be plugs in the end. It also showed no codes and only misfired when giving it a good amount of throttle.

 

[Hairyned]

Also an issue with an aftermarket exhaust or decat apparently. Mine does the same.

 

[KaitlinE07]

Possibly to do with the post cat o2 sensor then? I’ve had plugs replaced recently seems to be one of those annoying faults

 

[Hairyned]

Mine developed when I had the exhaust changed to a 3" stainless with a single high flow cat. Potentially a backpressure issue. Have you checked for leaks?

 

[KaitlinE07]

I haven’t checked for leaks yet but will deffo do that! Thank you!

 

[turkie172]

First thing remove the plugs and see if they are the correct ones (NGK PFR7Z-TG) and check for water or oil contamination as well as flash over on the ceramic body. Keep the coil packs and plugs in the same order from the plug you can have a good guess which plugs are worst and most likely the coil packs are faulty I fixed a 2008 Clio with two faulty coil packs they don't show up on diagnostics or codes. I had the ability to swap coil packs from my car to find the problem and I was surprised that two coil packs were faulty. O2 sensors can cause a fault I did have at one time an effect similar to a rev limiter but at low RPM intermittently until I had the RS tuner running live data and it indicated a forward lambda short circuit but the fault was not stored and if the car was turned off and restarted all traces were gone.

Note: when removing the coil packs the small bolts that hold them should only be 8Nm but are prone to over tightening damaging threads and remember how the VVT solenoid sits on the coil pack on the timing belt side as the bolt holds both in.

 

[bedoef]

Possibly to do with the post cat o2 sensor then? I’ve had plugs replaced recently seems to be one of those annoying faults

Likely this is the issue. Swap the sensors around and try going for a drive see if that solves the issue.