I just finished installing an inline fuel pump, and a vortech fmu. we went for a test drive and the idle kept on fluctuating. Anybody know why this is happenning? As long as the car is out of gear the idle fluctates from 1000 rpms to 2500 rpms. The throttle is acting as if i keep on revving the car from 1-2500 rpm. Any help or ideas that may solve this is grealtly appreciated. Thanks.

 

turn up the idle a little bit... the fmu doesnt do anyhting untill it sees boost. the inline pump raises your fuel pressure about 3-4 psi so try uping the idle maybe 100-300 see if that helps also clean out your idle air control valve if that doesnt work.

 

thanks for the advice. Earlier tonight i just re routed all of my vacuum lines and the car idles and runs great. Thanks.