After a Marelli meltdown, I had all of the fuel injectors rebuilt and calibrated, installed new coils, distributor cap, rotor, plug wires, and cleaned out the exhaust system on the A bank. When I started things up I had a rough idle. I changed the Coolant Temperature Sensor and there was a marked improvement in the idle smoothness.

I figured if the CTS helped the idle, changing the Air Temperature Sensor might be a good idea. I ordered a new Lucas ATS and installed it. Immediately on startup, I got an FF17 code. I cleared the code and got it again as soon as I started the car. I put the old ATS back in and no code issue.

Please help me to understand - was the new ATS defective or is there another issue that I should be looking for?