A170 cdi

[msk448]

Had 4 new injectors fitted last month and now the car will not rev over 3300 RPM but runs very smooth.... before I take it back to the garage, any idea's please.

 

[Tony Russell]

The problem I had, with similar symptoms, was that a hose had been crushed in the bonnet.
This seems to be a vacuum hose that feeds the turbo. It was fed from an acuator beneath the wash bottle, over the bulkhead and into the turbo department.
It might be worth tracing this hose for any kinks.