A/c works fine at Lower speeds

2002 Civic the ac works great at 45 mph or lower but at higher speeds it does not??? It does have a new compressor and not leaks and both fans are working fine .... Any ideas??

Start with the basics: get your ac system fully evacuated and recharged to the factory specs. Don't use a can, or a can with a gauge that indicates "blue" for fully charged.

The only way to properly fill an ac system is with a scale that most recovery and recharge machines have. It may cost you $140, but that is the only way to properly start the diagnosis of ac problems.

16 years as an ASE certified mechanic.