I'd say its probably time, even more so if you have no history prior to 132k. The OEM Bosch one is ~$120. If you are handy with wires and solder, you can solder the one from a 1990 Mustang GT as it uses the same sensor for ~$35 to the factory harness. MB just decided to charge $90 for the wire
The "standard" is every 60k...but I've heard the real interval is ~100k assuming no idle or mpg issues.