[dpadenmwd]

When driving around town without the a/c in 95-100 deg weather, temp. gauge is normal. If a/c is running temp runs hot. I have changed the fan clutch, water, pump, t-stat, and radiator flushed professionally, but truck continues to run hot when a/c is on.

[TxGreaseMonkey]

Likely, you need to replace the radiator, or have it rodded, due to phosphate scale buildup. Only use a 50/50 mixture of manufacturer-recommended antifreeze and distilled water, in the future. An IR thermometer may show relative cold spots in the radiator.

[RickMN]

We'll have to assume you did the obvious radiator fin cleaning on both the radiator and the condenser, right?

If so, then there are only two things left--the radiator and the baffles/shrouds around the radiator. Believe it or not, if the baffles or shrouds are missing, broken, or out of place, it can REALLY affect airflow through the radiator.

TX makes a really good recommendation with the infra-red themometer. You can pick them up cheap (around $30 for a good one). Then point it at several places along the water route and the radiator. It will immediately show you the spots that aren't cooling properly.