First of all, Happy Thanksgiving to you guys down South.

Second, the R50 in my signature is no more, it was rear ended, written off, and then I got a Dinan tuned 2006 R53.

The previous owner of my R53 told me that it trips an engine light P0172 (o2 sensor bank 1 fuel too rich), trips randomly, can't pinpoint what triggers it, but "a new o2 sensor will probably fix the problem" a new sensor in is upwards of $220 in Canada, I didn't want to play a guessing game with those prices. Any mechanic I took it too said there are too many mods on it they need a day to play with it. I can't afford a days worth of labour and a rental car.

The car runs perfectly fine with the SES light on or off, gets about 25 MPG according to the OBC, maybe 22-23 MPG realistically the way I drive.

Anyway, long story short I've been clearing the code and reading live engine data trying to diagnose the problem. Last fill up I used a bottle of fuel injection cleaner. 50 miles, no light, 51 miles I get a light for P1498.

According to my searches for this code on MINI's it means "unmetered air after compressor" which to me sounds like a bad TMAP sensor, but every post regarding this code on NAM says to look for a leak on a hoses and boots after the supercharger.

I'm new to the R53 engine, (the whole reason I got an R50 years ago was because I could diagnose and fix them myself) if it's not the TMAP sensor, what EXACTLY should I be looking at for a leak? Tell me left or right of the intercooler, etc. There's no oil catch can or boost gauge.