Idle it won't-03 ZX5

[joetc5]

Hi, campers. New guy here- posted this on newcomer section as well. I have an '03 Focus ZX5 with Zetec 4 and a 5 speed standard transaxle. On a 12 hour trip, stopped for fuel at about 9th hour on a very warm evening. Filled up and grabbed a bite - restarted- but engine immediately stopped with release of gas pedal. Ran fine but would NOT idle. Kept a foot on gas pedal and used emergency brake to stop (so I could keep a foot on gas pedal and clutch) until back on hiway. At end of trip (after dark, evening much cooler) when I pulled off NY State Thruway to pay toll- idle was back and working fine! Check engine light never came on!
Friends guess- an oxy sensor is crapping out when the car stops and it gets really hot under the hood with no air flow through engine compartment. When trip resumed, cool air thru the grille put it back in operation. Have had car 2 months- cool months- never had this syndrome before. Any info on a problem like this?? Thanks joetc43@lycos.com