2013 Infiniti G37 — catalyst efficiency code but car drives normally — buyer question from Orange County

Cleared nothing. I want service to see the alert on the 2013 Infiniti G37 first. Cold start is when I can actually reproduce it.

Ask what changed right before it started. A pressure test beats staring at a dry driveway if the 2013 Infiniti G37 is losing coolant with no puddle. Save the big job until that test fails. Verbal 'we'll take care of it' is not a plan. Video is ugly but it shows the hesitation.

Log the conditions before you spend. Move a coil or plug on the 2013 Infiniti G37 if it's cylinder-specific and see whether the code follows. That's the branch I'd chase this week. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. That's the sequence I'd use. Might be overthinking it, but I'd rather overthink than overspend.

I'd want a measurement, not a hunch. Two 2013 Infiniti G37s can feel identical and have different causes, so measure before you copy someone else's repair. If the cheap test changes it, stop and reassess. That's the sequence I'd use. Cold start is when I can actually reproduce it.

Start with the test that can prove you wrong. Write temp, speed, and in-gear vs coast when the 2013 Infiniti G37 does it — then decide on parts. That's the branch I'd chase this week. Time, temperature, and whether it's in gear are the notes that actually help a shop. If this is nothing, great. I want that in data.

I went back under the 2013 Infiniti G37 and it only happens after a heat soak, not on a cold start. Trying not to diagnose from the couch.

If it were in my driveway, a pressure test beats staring at a dry driveway if the 2013 Infiniti G37 is losing coolant with no puddle. If the cheap test changes it, stop and reassess. If they can't show the line item, I assume it's hiding. Not trying to scare you — just skip the expensive first guess. This is the version I'd tell a friend.

Log the conditions before you spend. Two 2013 Infiniti G37s can feel identical and have different causes, so measure before you copy someone else's repair. If the cheap test changes it, stop and reassess. On “catalyst efficiency code but car drives normally,” that was the fork that mattered for me. Run the total, not the monthly, before you commit. Climate here is different, so treat that as a local data point. Only after sitting overnight so far.

Ask what changed right before it started. Move a coil or plug on the 2013 Infiniti G37 if it's cylinder-specific and see whether the code follows. Don't erase codes until someone who can help has seen them. No need to make it theatrical. A day of patience here is cheaper than a wrong part. If this is nothing, great. I want that in data.

Start with the test that can prove you wrong. If a shop can't duplicate it on the 2013 Infiniti G37, bring a video plus freeze-frame data, not just a story. That's the branch I'd chase this week. That's the whole play. If that fails I'll eat the diagnostic fee.