We have a 1995 42m schwing, when slewing the boom left or right it speeds up when you use another function at the same time, it does this with both the wireless and hardwire remotes. When swinging the boom and you touch another function you can watch the manual lever for the swing come on harder. When you use the hand levers to operate the boom it does not appear to do this, we have changed the selinoid wires and still no change, we have also changed boom pump and some block on the side of the Hyd tank. Any insight would be greatly appreciated, it appears to be electrical but who knows.

The 'speeding up when using another function' is a typical problem in the load sensing circuit. Chances are, due to the age of your pump, you have a lot of internal leaks and bypassing, possibly spools worn out. Your problem is within the boom handvalve

Awesome thanks a lot for the reply we will definitely look in to it