Ranger thunder xlt 2.5td 04 2k revs only !?!?

[Dgt]

If you Unplug the map sensor (boost sensor) the thing revs like normal and has boost when driving , but only limp mode with it plugged in .
(Same with a new mAP SENSOR I BOUGHT)
I've cleaned the egr system which was completely blocked in 3 places and cleaned maf sensor .
Serviced it , checked fuses .

Please somebody enlighten me. No info on these models
I Can not even find the PCValve .
Thanks
Dale