Rough running PD150

[Thai-wronghorse]

So after owning my Leon FR for a couple of months virtually hiccup free the past few days haven't been so rosy.
Basically it's as if the volume of the engine has been turned up a fraction and the power turned a little as well.
It's still boosting well but the delivery isn't as smooth and has lost any kind of refinement it had when I first bought it.
MPG isn't particularly great either with it struggling to get low 40's on a run.
Initially I thought it was down to poor quality fuel as I filled it up around the same time but even with a dose of cetane booster (2-ehn) there's no improvement.
I've run my code reader on it which returned absolutely nothing so I'm kinda stumped as to what to check next.
Smoke is very minimal, certainly nothing out of the ordinary for a derv anyway.
If I hold the revs to around 1300 and creep it up slowly whilst parked it feels as if there's a slight misfire.
Idle is steady, albeit slightly louder than usual.
I'm going to service it in the next few days but I'm not convinced this will resolve it...
Any suggestions greatly appreciated.

 

[Matt.]

Still got the EGR valve on it mate? Also try unplugging the maf and going for a run to see if it's any better. May be worth changing the green coolant temp sensor to

 

[Thai-wronghorse]

The engine is completely stock at the moment so yes it's still running the EGR valve and standard boost pipes.
I'll whip the top pipe off when I get the chance to see if it's due a clean out.
I guess it wouldn't hurt to try the CTS and MAF either but it is warming up correctly according to the dash but you never know as they're duel purpose.

 

[nigxl]

I changed my CTS as I noticed my temperature flicker once or twice also I was struggling around the low 40s and always had done. CTS sorted it but go for the VW part not a copy.