I got some ???'s on my 87 4.0L performance issues
my 87 XJ 4.0L auto trans has 192,xxx miles on it right now, i have finished replacing the plugs, wires, cap, and rotor. soon will replace the accessory belt.
my question is, the header is cracked, cant really tell where it is cracked at. it just smokes at idle when i blip the throttle, can a cracked header really affect the engine perfomrance dramatically?
how do i find the timing mark? i have a timing light and i cant really figure out how to find the timing. i dont have a manual at all.
the timing chain, i have no clue when it was last replaced. I know chains and belts are different, belt can flex and stretch easier than a chain. Is it really necessary to replace the chain? how do i tell if its still good?