ericcaldwell

i have a 1993 grand cherokee limited with a 4.0 motor with 174,000 miles, i had a low idle in park, replaced the idle air control valve, replaced the throttle postion sensor, cleaned the throttle body, replaced the throttle body gasket and now idles at start up at 800rpm after 3-5 mins. goes up to 1500rpms and after 5 more mins will drop back down to 1000rpms. will do this regardless if engine is hot or cold. if i wait untill it drops and drive it, while i'm driving at a constant speed and shift into nuetral it will jump up to 1500rpms, or if i come to a stop and shift into park it will jump back to 1500rpms. checked the vacuum lines for leaks, cleaned the crankcase valves and lines, replaced air filter, fuel filter, plugs and wires, distributor cap and rotor and replaced the o2 sensor and the coolant temp sensor. i am at a loss, really need help! what else could i replace or check? it was fine until i cleaned the throttle body, then the idle start doing this. i should have just delt with the low idle! please help if you have any ideas or suggestions! email me at ecaldwelltinleypark@hotmail.com