My 19yo boy called me on his way home from work to say he might need me to pick him up. His 1998 Durango (4x4, 5.2L) had overheated and steam was coming out of the hood. So I load up with some coolant and headed his way. As he explained to me, everything was normal and the check gauges light came on and he noticed he was hot. so he pulled over and shut down and steam was coming from the radiator cap. When I got there the cap was cool and was loose and there was a little spray in the engine compartment, but not coated. He said he hadn't touched it, so I guess it had gotten loose somehow and blown coolant out. Plus I think he has a slow leak in the heater core, so I've told him a million times to keep the fluids checked until we can repair it. The radiator was practically bone dry...not sure how much it actually had in it, but I dumped right at 2 gallons of coolant into the radiator. When he started it back up, it was idling rough. No check engine light but I pulled the codes and he had 3 pending misfires, cylinders 1,3,7 and then the check engine light came on. I checked the oil and so far there's no coloration and there's no smoke coming from the tailpipe, so hopefully he hasn't warped a head. But I don't know what could be causing the rough idle and misfires. Could he have fouled a plug or three? I can't think of what else might cause this besides a blown gasket, but so far that's not indicated. Hope you folks might have some ideas on which way to go next. Thank you for your time!