Hello @problemcar
Just thinking, what It could be:
* Air weight
*
[image|1868696]
* Exhaust system leakage
* Engine leakage
* Accumulated deposits on the combustion chamber walls, but also on the pistons
* Wear of cylinder inner surfaces
* Wear of compression piston rings
* Valve N75
It’s difficult to say, just only thinking, if somebody will know more information, would be better then these ideas, but nobody can diagnose your car without manipulation and measuring.
Better then the forum is repair centre…