Try this, have your condenser cleaned at a carwash. Aim the water jet in front of the condenser. Chances are your condenser fins are blocked by debris (mud, muck, dirt, insects, leaves, etc.) When these things get wet, they are not good heat exchangers, and they expand, thereby thoroughly (or partially) blocking airflow.

Its a practice of mine to jet-spray the front part of the condenser everytime I clean our daily driver. You'd be surprised on the amount of debris that gets clogged in between those fins.