Truex came in as the polesitter and was one of the favorites after leading final practice. He was also running the same car that dominated to the tune of leading 392 of 400 laps in the Coca-Cola 600 on Memorial Day weekend at Charlotte Motor Speedway.
The Furniture Row Racing Wheelman led the first 16 laps of Monday's race at Pocono before a scheduled competition caution.
Brad Keselowski and Greg Biffle, who stayed out, were the lead cars on a Lap 18 restart.
During that restart, Paul Menard lost power and fell back in the field, causing cars to maneuver around him. Menard went to the garage and appeared to be done for the day.
Goodyear tweeted out the official diagnosis on both of Truex's incidents.
