carfax seems like it could be semi accurate. i was under the the impression that i was in the 200k + range when i bought my monte, cause of the price and severe paint fade. i got the title and looked at and it confirmed what i thought. so i stopped thinking about it. but then after driving it for a year with zero major problems, cept for the trans goin after purchase. i thought back looked at the window sticker from 02 registration, remembered the guy said it sat since about then. did a carfax and it actually confirmed in 02 it was sitting at 101k and in 98 it was confirmed at 77k. so i remembered to back when i bought it, and the odo was at around 101 k, i was thinking 201 k. but i think i have 110k car now cause there is litle rust and certainly not enough mechanical wear for 200k. so id run a carfax it could give you an idea. the only thing ive seen somthin like the red light thing was on my old beater tracker, when it hit 200k the check egine light came on and you had to pull some pieces off the dash to find a switch that reset it. i think it did this every 100k