valve seat problem

[BARanger]

The problem all started with the engine running a little rough at idle. Then I got a engine light with a cylinder # 1 misfire. Check the wires, plug, injector,
coil, everything was ok. performed a compression test had 90 on the first test
then 120 on the second all the other cylinder had 150 psi. pulled the head took them to the machine shop and they said the exaust valve had flatten and the valve were reciding into the head. All the exaust valve were doing the same thing it had a leaking valve on the # 1 cylinder. He said this is mostly cause by heat. I read on some of the other post that the 3.0 had a problem with the vavle seat. does anyone know what might have cause this, when the motor has never over heated, and was jut rebuild 15k miles ago
and the head were serviced with new seat and 3 angle grind. They said they canput in overside seats that are strong than the ones that are in there now does anyone have any idea that could cause this without the motor running hot or overheating especially on a motor that has very few miles. it a 96 3.0 4wd

 

[Big Jim M]

Miles cause the valves to wear and also the seats.. Then when rebuilt the head shop grinds away even more of the valve and the seat! That's proly what happened to your ride.
Big Jim