24 valve, v6 mercury sable sounds like the valves are tapping but runs fine - what could be the problem

What you should start off with is flushing the motor purchase motor flush from advanced or auto zone (probably best price) read directions do not rev up motor idle motor i usually flush the engine 3 minutes longer shut off then wait one minute then restart for 1-2 mins and ralph makes a good point quit running 87 octane if you are because it\'s actually terrible for the plugs fouls out plugs quicker builds more polutants in tank and is not healthy for valves or emissions system and is number 1 reason for check engine light coming on wait run the tank low purchase mystery oil insert into fuel then fill atleast half tank with 93 octane purchase motor honey and new oil and oil filter perhaps 10w-30 synthetic then get your motor flush poor entire flush into engine make sure dip stick is in between add and full or C&H with oil before pouring check on flat grounds ok now start the vehicle run for up to 7-11 minutes shut engine down wait 1 min restart for 1-2mins ok now drain oil make sure its drained meaning let it drain for about 1-2 hours if you need to if your drain plug is located towards the rear of engine jack the front end up some to clear the rest out now screw bolt plug back in hand tight no tighter put little effort into turning if your strong armed change oil filter(hand tight) pour motor honey into engine then pour new oil into motor(check recommended quarts for your engine in handbook)probably 4-5 let sit for about 5 mins for oil to sink into engine then start engine let idle for about 5 mins before reving engine(to reduce wear on engine)let the motor honey do its work if you wish just let vehicle idle for 30mins then drive around sound should now have dimmed down if theres no serious damage done get on highway press gas 3/4 way down to kick engine a little to help get that crap gas out of vehicle and help clean fuel injectors or if its straight drive rev to 5k rpms between 1st and 2nd gear this should help you out continue to atleast run 89 octane maybe every other week or so use fuel system cleaner pay for complete not the cheap crap the extra 2 dollars for good fuel system cleaner is worth it by using the cleaner every couple weeks and running atleast 89 octane in vehicle you will see and notice an increase in lost power and gas milage soon enough and becarful using pumps if they have high percentage of ethanol do not use it its terrible on engines i think it should be made a law to keep that crap out of pumps

This could be many things, worn rocker arms or rocker arms out of adjustment,worn or plugged push rod, plugged oil pasages to top end of head or low oil preasure, the valve covers will need to be removed to check the clerance on the rocker arms, hope this helps.

To to a higher grade of fuel it might just stop pinging