im looking at a rebuilt 95 gst, the kid is young his father showed me the recipts and the engine was rebuilt,but it also has a 20g turbo,greddy frount mount, 3"downpipe and 3" exhaust, it HAD apexi safc and the apexi avcr (both stolen) and the car runs rough and shakes the whole car at idle at 1500-3000rpms it runs like a champ then 3500rpms it runs just as rough down the road then when it gets to 4k and the turbo is kicking in it runs perfect without a miss or sputter, what could be the problem? he said it hasnt had a tune, and its running 10psi of boost, any ideas how 2 fix this?

A tune would fix it. Be careful tho because they may just be saying that it had a afc and avcr when in reality its never had a tune at all.

it did have a tune back in the day, the car was broken into and those were stolen he rebuilt the car got it running but said he hasnt tuned it yet, so the way its running is just out of tune? i mean once u get to 1500 it runs fine till about 3500 it runs rough then 4k it runs perfect again, and would throwing a greddy e-manage work? also i seen the harnesses for the apexi's they r still in

someone on here just bought a car recently with the EXACT same situation. see if you can search for it. it might just be coincidence but you might be getting the same car