We have had a problem with our "Service Engine Soon" light" displaying constantly. The dealer's service tech said that the diagnostics indicated that there was a slight emissions leak, and that it had been caused by the Locking Gas cap (which we ordered and purchased from the dealer). He claimed that these gas caps don't seal as well as the stock cap, and said that we should replace it with the stock cap. Has anyone else experienced this problem? Makes one wonder why they sell them if they are problematic.