blow up the tire, put dish soap and water all over the tire and where it seats on the rim to find the hole first, if the leak is in the lugs then patch it, if its around the rim take it to basically any tire shop and they will reseat it. if there's a hole in the sidewall it will need to be replaced
yea the mud guards were stalling production ever since the first maverick was released. its probably too late now but i would have just bought aftermarket ones. the oem ones are shit anyway