Hey all.New to the board. My 2002 Ranger xlt fx4 4.0 auto is "Bucking" under load and has a lean cond.pinging like a *****! New plugs,wires,coil pack,fuel filt.Shop checked pcv,egr,air controler,cleaned all plus the throttle body. New maf sensor. Checked intake for leaks,all tight.Knock sensor adjusting timming ok. HELP!!!!