Have you any fault codes?

When 1.7cdti combo did this it at that rpm It was a clogged fuel filter and sticky egr valve.

 

No check engine light and error code.
Fuel filter has just been replaced.
Will check the egr valve.
Thanks for the Tipp!

 

Today I noticed on the highway that in 5th gear around 80km/h/1700rpm my egt temp is about 350-400degree celsius. In this stage i feel the misfire.
Then i shift into 3rd gear and cruise at 70km/h at around 3000+ RPM and noticed no misfire! Interesting is that the EGT temp is around 250 degrees celsius only.
Actually I expected that the egt is higher with higher RPM.

I read that high egt temp means that the air fuel ratio is (too) rich (there is too much fuel or too little air).

It was mentioned that it might be a sticky egr valve.
EGT valve recirculates exhaust air into the combustion chamber right? So if this is not working properly i have not enough air = to much fuel.
In which RPM range is the EGR working?
Is it possible that a sticky EGT valve is causing this issue or which component causes this issue?
Btw which EGR type is the z17dth using?

thanks for your input in advance.

 

So you say EGT should be in line with engine rpm. Wrong buddy. EGT is in line with engine load.

Second, I've spent good time of my life doing research on misfire detection and analysis and learned that on high rpm, the shaft rpm variance is so little, that even the engine ecu cannot detect misfires.

I even build my own tools and software, was fun.

 

Thanks for teaching me TTT!
Makes actually sense.