Engine wont rev past 5000

SO I finally got some time to fit the new knock sensor (have a 6 month old baby so time in short supply). I also replaced the thermostat as the car wasn't getting warm.

The car is much better although still hesitates on occasions, this time around 6k revs. My feeling is that it has poor quality fuel in it, it just feels sluggish. I'm going to run through the remaining 1/4 of a tank and put a tankful of decent fuel in it.

Think I'll also change the plugs so I know they're not to blame.

Cant think of anything else it could be?!
 
Did you ever solve this problem? I have the same issue. Also changed my knock sensor but didnt fix it
 
Did you ever solve this problem? I have the same issue. Also changed my knock sensor but didnt fix it
It only partly solved the issue. I also did the MAP sensor fix and ran a tank of 98 RON fuel through it and then it was perfect. It’ll only run well on 98 RON fuel which seems to be common
 
It only partly solved the issue. I also did the MAP sensor fix and ran a tank of 98 RON fuel through it and then it was perfect. It’ll only run well on 98 RON fuel which seems to be common
I always run 98 RON but still have the issue. I believe my problem may now be the fuel pump