was doing reverse doeys one night (very stupid idea) any way sub box went flying and amp inline fuse blew. Replaced fuse and now my amp goes into diagnostics, my sub keeps making this repeating thud sound anyone have any ideas what i can do to fix this ? its an earthquake amp if that helps.

Congratulations on stuffing an amp...
Yes Reverse Doey's is a bad Idea, not only does it prove nothing but places excess stress on CV joints and suspension components..

If you sub is making a continous Thudding noise then the Amp is stuffed..

why be a wanker i did it learnt from it and am over it what is it to you ?

You left yourself wide open to ridicule after stating you did reverse donuts..
You could have stated your sub box was thrown around due to excessive cornering and no one would have known..

as long as you have learned from it then cool...

You wanted to know how to fix it..
You have been informed it is stuffed,send it off to be repaired or replace it...

hey man also check the ground fuse on your head unit if the sound on the sub persists my sub was going crazy thunpin when my ground fuse in the head unit blew

Ziff we all havent done stupid things at some stage...

Check wiring, ensure none has frayed and is shorting out anywhere, (sub, power etc)

Yea, id say the amp is just stuffed. Send it for repairs if its expensive. Or if you like you can try and open it urself, do some testing see whats blown. i dunno.. but the amp is gone, ive had a few go on me and it does the same thing.

Thanks for the help i tryed it out on my mates car and it worked fine so redid the wiring for the amp in mine everythings workin fine now thanks again

Your wiring may hav been thrown around and shorting out.. Good to see all is well..