what do I do next with troubleshooting A/C system?
 

I have a 92' Ford Ranger with 2.9 V6. It uses R-134 refrigerant. 11 months ago I had major work done on the a/c system: new compressor/clutch/hub/field, hoses, belt, relay, evacuation, and re-charge. He did not replace the accumulator and orifice tube like he was supposed to.He didn't flush the system either.

Two weeks ago, the compressor clutch started blowing warm and cyling on and off every eight seconds.

I took it to another mechanic about a week ago. He said there was too much lubricating oil in the system, which he drained from the compressor. He also found a little bit of the "black death" also.He replaced the orifice tube, accumulator, o-ring, fan clutch, and flushed, evacuated, and re-charged the refrigerant. He also did two leak tests with dye.

The other day, I ran the a/c for about an hour driving home at the highest setting. It blew at neutral termperature for a long time before it finally started to emit a little bit of cool air. It did not perform well. It was about 108 degrees here in Phoenix.

But this morning it blew nice and cold in a very short time.

Now here is something else I noticed. There is a pipe going to the condenser with a valve fitting similar to a tire valve stem. I believe this is called a "service port." The mechanic forgot to replace the cap on it. Someone said that if the cap is left off, it can cause a leak. Could this be the problem?

I also noticed that the compressor seems to run continously. Isn't the compressor clutch supposed to cycle on/off at least some of the time?

Where do I go with this now? Could I have a damaged compressor because the first mechanic didn't do a thorough job?