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      01-14-2013, 11:57 PM   #1
Lieutenant Colonel

Drives: 2009 Crimson 328i
Join Date: Oct 2012
Location: Los Angeles

iTrader: (0)

TPMS warning and reduced performance

The manual seems not to suggest anything of this sort takes place, but from your anecdotal experience, does your car derate its performance when a tire pressure warning is indicated?

This weekend my roommate and I drove a couple hours north to visit a friend and on the way back down I got a tire pressure warning. I'm pretty sure it fired due to a huge temperature swing on the trip and an overnight rest (65 in LA, 18 in Tehachapi), since when I checked at home afterward, all the pressures were about in-spec (maybe 1-2psi down max).

I noticed on that trip back that the car felt much more sluggish and unhappy than normal, mostly in the power department. I didn't notice this on the way up at all, but obviously there's a lot of room for subjectivity there. Anyway, I got the car back and checked the tire pressures. For good measure, I topped them all off (and in fact, topped them off to the 100mph+ spec, so a few PSI higher than the normal factory pressures). I reset the TPMS and took off, and the car felt much, much better, totally back to normal.

Some of that could have been the pressure change alone, a lot of that could have been my roommate no longer being in the car, but the pressures weren't FAR down and the car felt great on the way up.

Anyone else ever notice this, or am I just off base?