TPS is throttle position sensor. Doesn't have anything to do with timing. The sensor just measures the throttle plate angle. Very important sensor. It's an analog sensor, meaning the signal varies in voltage with throttle angle. So if you're getting a TPS code, that either means that the sensor is bad (or the wiring is bad) or that the sensor is horribly miscalibrated. Most of them have some adjustability in the mounting such that the sensor can be rotated to match the start point of the angular range with the proper voltage level at that start angle (so the sensor puts out the correct voltage at that position). Generally a mis-calibrated TPS will make the car run poorly, as the airflow into the engine doesn't match what the sensor reading is telling the ECU, but it generally won't trigger a CEL. Most sensor cells require the sensor to be pretty far out of the range the ECU knows to be normal. This is why most automotive sensors read between 0.5 and 4.5 volts, so everything above or below that range can be properly detected as a fault.

That being said, my natural reaction when someone has a SR sensor fault is to blame the wiring. I've seen some horribly fucked up swap wiring, and it doesn't surprise me at all when people have tons of problems getting the engine to run properly. This may or may not apply to your car, but that's always the first place I would look in a swapped car. It's easy to check continuity across the wire from end to end, and check for shorts to ground, etc. Once that's out of the way, you can check to see if the sensor is working properly. TPS sensors are so easy to check though that you can just do that first and then figure out why you're getting a fault. Remember that you have to have 5V, ground, and a signal all connected to the ECU for the sensor to work, so don't just check the signal wire and assume everything is fine.