i have a 1993 cherokee sport 4.0l it idles very rough and runs rough at steady speed i have replaced the plugs,cap,rotor,wires, and the map sensor i have cleaned the throttle body and idle valve. I have no codes, 19 inches of vac at the intake and all sensors appear to be working properly i have 30 psi of fuel pressure and plan to replace the fuel filter tomorow amd then i will recheck fuel pressre to see if i need a fuel pump any help would be greatly appreciated.