We recently bought a '97 Dakota 3.9 for my son's first vehicle. Overheated on the way home, so changed the thermostat and attempted to drain radiator (petcock is apparently clogged). Now trying to figure out why it suddenly stopped running while I was revving it at 2,000 RPM to get the engine heated up. Wouldn't restart, so I borrowed a fuel pressure gauge and by the time I got back, it was running again (fuel pressure is a fairly steady 43). Going to pull the plugs and check those next. Anything else I should look at for an issue like this?