a miss is fuel or spark related and can also be a sensor or ground problem.
my 89 would stall out(if i dont give it gas and let it idle on its own) after the first start when cold or have a slight miss if it didnt stall because i gave it gas. if it stalled after the first and had to restart, everything was fine. it was only a problem on the first start when below 35 degrees.
what cured that problem for me was most likely a combination of a few things. i readjusted the tps and verified it had a good ground(terminal b), did a top end cleaning with seafoam, cleaned the throttle body and iac, and cleaned the ground wire that comes out of the main wiring loom going into the firewall near the booster. the wire coming out of that big wire loom is a black ground wire in front of the winshield washer resivoir and goes to the driverside fenderwall in the engine bay(ive owned the xj since 1990 and never noticed this ground wire). i also cleaned the ground that is under the coolant expansion tank bracket. i already have a second ground strap at the back of the head to firewall.
since i did all this last year(along with cap, rotor, and champion plugs) it starts up fine and will idle perfect without any stalling or miss fire when its cold out.
