I have a ticking noise on the left side inside my engine, I think its a sticky lifter?

I have a 2002 dodge intrepid with a 2.7L engine with 103,000 miles.I had just bought this car 2 months ago, one day it started to make a ticking noise, within a half hour it got louder and louder, I quickly put a quart of additive in and after 15 minutes the noise went away, I then added a quart of oil sludge cleaner and ran 5 minutes and drained the oil and put a new filter on. The old filter was heavy I believe with sludge. The car ran great for a few weeks then the ticking came back but not as loud, so I stopped at a quick oil change place, they drained the oil and put a 1 gallon cleaner in it and ran it 5 minutes. The ticking went away. I then had them put 5W20 in for the oil. It was good for a few days but now the ticking comes and goes, varying in loudness. I also wont to mention that on the another sight they said the 2.7L engine was originally designed with1/4 inch oil port holes in the engine, but to meet emissions they ended up putting in 1/8 inch holes instead. They also said to run 5W20 oil. Does anyone know what I should do next?