Ok my a/c use to blow cold on n off meaning after it ran fa a lil while it would blow warm after blowin cold so i took it to a friend of mine shop and he used that suction machine to get all the air out then we ran the system on high and put 2 bottles of r134 in the low compensating port it it just blows warm now doesnt get cold like it use to he told me i might have a clog tell me how to solve this problem.