thanks for the reply chap.in short yes ive done all them and more. had to change ecu last winter because of another issue self inflicted. it revs out to about five and half nearly six the base lift on the waste gate actuator should be 8psi my 31 is starting to operate at just under 4psi so im loosing boost pressure by half. theres no mis fires its clean all way through. i have a ggr racing one coming another 31 these are well known for springs giong week it is twenty year old.i wounder what the bes way to check for boost leak is with an airline may be i could take out the dump valve make a bung drill a hole through it and put my coolant pressure tester on it and pump it up or start reading the work shop manual. ther is hissing noise when im ecselerating theres nothing obvious the dump valve is good. may be the hissing is the boost going past the waste gate flap. if royalmail pull there finger out i could find out today