Operating off assumptions, pulling trailer ( or any sustained load) can cause the cat converter over temp protection the act. The PCM adds fuel to cool the converter. Where your trims are pulling close to the limit of triggering a P0172, this enrichment would push it over the limit. You wouldn't necessarily see this on you LTFT.
It's a very common practice in tuning to raise the COT limit which may be why the tuned PCM had no problem. To diagnose further you really need freeze frame data from when the code is confirmed or you need to monitor the live data.
It's a very common practice in tuning to raise the COT limit which may be why the tuned PCM had no problem. To diagnose further you really need freeze frame data from when the code is confirmed or you need to monitor the live data.
