as far as diagnostics go, considering I still know jack shit about cars, I just doing a clutch test on it and throwing it in 5th gear with high rpms and the clutch didnt slip (which is good its brand new). As far as the other stuff the only thing I know is When starting from a stop, it shakes very violently. I took it to my mechanic and he suggested a vaccum leak at first, but when I finally dropped it off he claimed he couldnt find any leaks and so far he has hooked it up to a bunch of computer diagnostic stuff which cannot find any issues with the car.