Simptoms like a bad injector , but ...

[radujohn]

I had a mechanic check and it is not an injector.
His scanner was reading a bad injector #3. But when we opened we have seen that the injector was changed ( looked new ).

I forgot to say ... 2005 F350 with 6.0 L, 459000 KM ( about 300000 miles ), bought at auction.

So , engine running but lots of white and blue smoke, not much power until turbo kicks in and the engine is shaking.

When the mechanic checked the injectors he said that it shows that injectors are fine , but pistons #3 and #5 seem to be dead ( not functioning ).

I would start tearing it apart , but I would like to know what would be the problem.

Rest of the engine seems to work fine, oil pressure is good , temp is good.