i had a turbod GSR that ran good but the turbo went out and i put the 4-1 header back on and it wont idle it dies but it runs good full throttle but when you let off the gas it dies it has a 2.5 bar map senser and we thought that was it so we put the stock one in now it wont even start it still has 760cc injectors in it still but i would think that would have nothing to do with it