2000, 4x4, 4.0L 6 cyl engine running very rough
its a 2000 4X4 with a 4.0L 6 cyl engine.
it running very rough at idle, rough when cold but when the engine is finally warmed up it runs even rougher, no power, shakes and shudders under a load.
i brought it to a mechanic and he checked wires, plugs, coil pack, compression test and vacumm test all passed.
I have also noticed when the truck is good and warmed up a sulfury smell comes out of the tail pipe.
could this be a catayltic converter problem? what i have missed in trouble shooting? would a ignition module be the problem?
getting ready to pull my hair out!!!