Temperature gauge reads over 3/4 when driving
Higher with A/C on
Normal temp at Idle
Has never boiled over yet!

Am aware of head gasket problems on this model and year, but see no signs of water coming out of tail pipe or any leaks.

Previously replaced leaking water pump (1 yr ago)
Replaced thermostat now
Cleaned radiator with heavy duty cleaner (one that claims to even remove "solder blooms")

Problem is similar to a slipping belt
What about air purging ?
Could EGR be pumping hot air into cylinder?

Going for block test at radiator shop Monday
Help

I would take it the a rad shop, and have the radiator and block power flushed.