'91 Lesabre Custom, 365,000 and still rollin'.
Currently in the middle of a full sensor package upgrade/replacement. Has a shifting/surging problem between 30-50 mph going uphill in second gear that I'm still trying to track down (think it's either of TPS, MAF, VSS, TCS, or Torque converter related). Starter seems to be weakening so I want to replace that, too. Shocks, springs, etc. also... all the stuff you'd expect on a 21-year-old car that hasn't had a serious parts overhaul in maybe a decade and gets drove 100 miles a day. ;p
Used to be my grandpa and grandma's until they passed and I sort of inherited it. I've abused my baby, but I'm keepin' a closer eye on her now. Have let the oil run low (twice), dealt with a bad trans leak for the longest time (fixed that), and overfilled the oil once. Overheated once or twice on me when I let the coolant run low. Still goes strong. Built like a tank.
😎 Needs a bit o' body work (grille, hood, rear right bumper panel) and roof headboard.
I could probably run this engine all the way to a million miles if I wanted, but I think I may want to rebuild it anyways along with the transmission around 400,000 miles 'cause I would figure that with 1-2 million revolutions on it the piston ring seals have got to be slowly wearing completely out, and if I remember right, the last time I did the sparks a touch of oil was on a couple of 'em, so that's an early indicator. Anyway, when the trans decides it wants to act fine, I still blow these little pissant Japanese cars off the road.

Faster than folks think it is.