PA-34 High RPM and low Manifold during ground run

[mahipal]

So we have this PA-34 whose engines are new and the props have been recently overhauled as well. The test flight is yet to be conducted.
During ground run what happens is we get higher RPM against the manifold on left engine only. While on full throttle things are normal i.e. 2575 RPM and Manifold Pressure of 39".
The gauges are not faulty. Checked the lines and they are OK too!!
Thanks in advance!!

 

[Avidflyer2]