McElvain scrambled to his right then back across the field before finding Weston in the left end of the end zone with 14:14 remaining.
Austin Evans and Bryce Flater picked off passes later in the quarter to thwart the Bengals (1-2). Omar Brown also had an interception for the FCS No. 8 Panthers (2-1) and Elerson Smith collected three sacks including one on Idaho State's final possession.
Kevin Ryan kicked two field goals for the Bengals before Matthew Cook hit one for the Panthers to cut Idaho State's lead to 6-3 at halftime. Cook added a 20-yarder with 2:11 remaining in the game. He is perfect on eight attempts this season.
SEC's Greg Sankey expects no issues with Big 12's Bob Bowlsby on CFP committee
SEC commissioner Greg Sankey told ESPN he expects to continue to be able to work with the Big 12's Bob Bowlsby on the CFP's management committee in spite of what has become an obviously fractured relationship.
SEC unanimously votes to extend membership to Texas, Oklahoma
Heather Dinich explains what comes next for Texas and Oklahoma after the SEC voted to extend membership to the two schools.
Will Texas, Oklahoma really move to the SEC? We answer the biggest questions
There's a lot to be determined as Texas and Oklahoma take the first steps toward leaving the Big 12. Our reporters break down what we know and what questions remain.
SEC unanimously votes to invite Texas, Oklahoma; Big 12's Bob Bowlsby 'disappointed'
The SEC voted unanimously to invite Texas and Oklahoma to join the conference, and the two schools could officially accept the offer as soon as Friday.
Texas, Oklahoma and the SEC -- Eight takeaways for a potentially seismic change
What's next for the Big 12? Is the SEC the first new-age superconference? And what about Notre Dame? Bill Connelly analyzes what could come next in college football's latest round of potential realignment.
ESPN responds to Big 12 letter accusing the network of trying to 'destabilize' the league
ESPN says it has "engaged in no wrongful conduct" in response to Big 12 accusation that the network is trying to "destabilize" the league.