Frankie Muniz had a real scare when the star was involved in a nasty crash during a NASCAR Craftsman Truck Series Championship Race … and was seen limping into an ambulance.

The race happened Friday in Phoenix … obviously ending for the star-turned-driver who was involved in a multi-truck pile-up on the raceway.

Right after the wreck … Frankie sure did look like he was hurting … captured on video limping and hunched over, but walking under his own power.

Thankfully … it looked way worse than it was … and FM seemed to be feeling OK when he spoke to the press not long afterward.

Assuring fans he was not badly hurt, Frankie said … “Unfortunate. I got a good opportunity to run with some guys, I made some passes. Lost a few spots on restarts, then went back out and passed them again” — which is when he got hit.

Prior to the race, FM said on X that he was super psyched … the actor has a long history with racing — including 14 races during the 2006 Formula BMW USA season. He made his stock car racing debut in 2021 … and over the summer announced he’d attempt his NASCAR Craftsman Truck Series debut at Nashville Superspeedway.

Fellow actor-racer Patrick Dempsey told us earlier this week he was pushing for Frankie in the Truck series.