I have a '03 prerunner. Just added 134 to the a/c, the a/c clutch cycled normal (cycled at about 1 minute or so). Now it cycles like every 15-20 seconds and doesn't blow as cold as it should. It's not over charged, guage shows in the safe zone. Is there a relay or pressure switch that could be causing the quick cycling? Truck has 60,000 miles. Any help would be greatly appreciated.