I recently purchased a 2002 vette. They told me it had an ls2 swapped in but seems like a franken motor. Ill find out later if its actually a 6.0 or not. But it was still on stock ls1 tune, so i took it to a local tuning shop and they told me to go buy a wiring harness for the engine and swap it so the thing didnt leave me on the side of the road when some splice came loose. So i did this, and got the engine to crank and fire off but it backfires and dies pretty much immediately. Had to splice in my VSS because they used some mass connector for all the sensors in the back of the car, (fuel level, pressure, vss, reverse lockout. Etc) but everything that is neccesary to run the engine should be hooked up. Pulled the codes and i get p1518
DTC report
Selected brand: Chevrolet

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P1518
Raw code: 1518
ECU: 10
Status: Pending
OBDII: Intake Manifold Runner Control (Stuck Open)
Chevrolet: Throttle Actuator Control (TAC) Module Serial Data Circuit; Electronic Throttle Module to PCM Communication

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P1518
Raw code: 1518
ECU: 10
Status: Confirmed
OBDII: Intake Manifold Runner Control (Stuck Open)
Chevrolet: Throttle Actuator Control (TAC) Module Serial Data Circuit; Electronic Throttle Module to PCM Communication
If i unplug the tac module from the pcm the car will start and idle without backfiring but its a little high. And throttle pedal seems to be dead wether its hooked up or not. I drove this car since may 5th of this year with my only issue being burnt ignition switch contacts, so i know the tac module APP and TPS are good. And its a brand new harness. throttle body and tac pins look perfect, and i haven't messed with the app yet. Anyone got any ideas what my problem might be?