Hope someone can help my automatic P38 revs on most gear changes ive changed the filter and oil in the autobox but still the same has anyone come across this before and whats the fix.

The autobox ECU 'cuts' the throttle during gear changes on an auto. It also controls the 'shift pressure' relative to the throttle position.

Check the TPS with a multi-meter. Try flushing the box with ATF as it might also be a sticking valve in the valve block (even tho they are solenoid controlled). Check the loom on the box and all the plugs are clean as well as the loom to the engine ECU (this is how it cuts back the throttle) Last thing would be to get you autobox ECU tested.

HTH