2008 Focus LT TDCI - lack of torque

[AZ_567]

Hi guys, it's my first time in these forums and I'm seeking some advice with regards to my 2008 Focus TDCi (6-speed manual).

The car has about 184,000 km on it, serviced on time (last service was at 180,000 km). I've recently got tires replaced, other than that, the next item due for replacement is the drive belt but that's not expected to be due until the next service.

This problem started last night not long before I reached home. I noticed there's an obvious lack of torque past 1500 RPM, normally at 2000 RPM you will easily feel the might of 320 Nm shoving you into your seat but it didn't happen this time. The car still behaved the same lethargic way when I drove it to work this morning. Overtaking needed a lot more throttle than usual.

I was very afraid that it's something wrong with the turbo but I was told that if the turbo's bust, you'd be seeing black smoke coming up from the exhaust (not sure if this is necessarily true). What other faults do you reckon this could have started from? A leak somewhere, or an injector issue?