Modify your signature to include your vehicle and you'll get more useful responses. Not knowing whether you're dealing with a 1986 carbureted 2.6l 4 cyl. Gen I or a 2006 3.8l V6 Gen III makes any diagnosis pretty much a shot in the dark.

95 Montero SR
3.8 MIVEC, Advance headers, 2 1/2" exhaust, Magnaflow muffler, OME shocks & rear springs, 2" body lift, 3" tank lift, 4.90s, TRE front locker, factory rear locker, Roger Brown Rock Sliderz, 315/75r16 (35") tires, Sport big brakes