It's not PATS. If you said the anti-thief light flashes after you put the key in, the story would be different. The light will flash without the key in.
Do you hear a click when you turn the key. Sorry, I am not more helpful.
new engine,1.7 rocker arms,Pipes exhaust, shorty cats , shorty headers,under drive and overdrive pulleys,4.2 upper plenum, throttle body spacer, cold air intake, stage one clutch, shorty shifter, and tune. 8.8 in storage