My 1986 Bronco had bad Valve cover gaskets, VERY COMMON ON 2.9 LITER ENGINE!!!!!! replace them with felpro brand, be sure not to over tighten the bolts on the covers and pay attention to the special washers that theY go back in the correct position. GOOGLE " BRONCO ii 2.9 ENGINE" READ ALL ABOUT IT.
New Gaskets about 12.00 bucks and felpro gasket adhesive 2.00 bucks.
I am also having engine sure issuse and sputters when warm.?????
still trying to figue that one out
Good luck
Ronfox01