I have a 93 GT with an SQ-Trim Vortech and tomorrow i bring it in to the Dyno. For a long time now, my Mustang pings on 5th gear.

I've posted on several boards, did my research and pretty much did everything imaginable. This Mustang of mine is stubborn.

My only solution now is to ditch the mail-order chip i've been using and get a custom tune (SCT). The mail-order chip (Autologic) did fix some problems such as idle and surging, however.

Any recommendations on what to tell the tuner to look out for?