I would just buy some tail lights like these:
http://cgi.ebay.com/ebaymotors/Taurus-SHO-Tail-Lights-taillights-headlights_W0QQcmdZViewItemQQcategoryZ33716QQitemZ7990838935QQrdZ1QQsspagenameZWDVW
Then smoke em.
I had the same exact problem with my atx, but it stopped when I got new wheels and tires. I have no idea what it was, something with the wheels and tires though.
Well after going through and checking about everything I could, I decided to start pulling the wires to see if the car would react, just to see if I had a bad wire or one wasn't connected all the way. Well sure enough number 6 wasn't right, so I made a little love to it and the new toy RUNS LIKE...
And oh yeah, I was reading in another post about remembering to reconnect the sensor that is at the back of the intake...I don't remember any sensors at the back, just vac lines going to a cylinder thingy, a place on the passenger side of the manifold, and a thing close to the cylinder thingy...