Don't suppose you have approximate RPM readings to go with those temps? In any case, step one is to verify the charge level. This will probably mean pulling it all out, vacuuming the system, and weighing in a new charge, with accurate equipment. And of course, this requires that the system has a spec for a complete charge. Some trucks can be problematic in that regard. Slight differences in the length of lines, or differently sourced components (common in trucks, especially if dealer or builder installed A/C), can throw charges off by quite a bit.

Do you have access to a good set of gauges?

MV