1992 maxima se stall out when reaching temp.

[hartman292]

I have a 1992 maxima se ve30deShe turned off doing 85 mph down the freeway with no forwarning.After replacing all the obvious things plugs, air filter, crank angle sensor, and checking for vacuum leaks and combustion, she will now run fine until she gets up to temp. and then stutters to a stall and will not restart until she cools back off. We also had to replace the platinum plugs with copper to get this far. any ideas would be truly appreciated.