I have a 1999 jeep grand cherakee larado that has fast idle problem I have replaced all vacuum lines throttle body gasket Cleaned throttle body idle air control valve throttle poison senser .

recheck the gaskets possible vacuum leak --others are plugs not gapped right-plug wires not on correctly or damaged/worn popped or damaged vacuum line --sensors to throttle body not connected or damaged ---throttle body needs relearn ---

Do you have done,tune up,fuel filter,coils,module,wires,plugs?

Intake gaskets? IAC valve bad? MAR set too high? Computer failure? Wiring to IAC bad connections? TPS not set to spec?

If you're losing fluid there's only one place it can go besides on the ground check your radiator the transmission cooler lines go to the radiator

Check for loose throttle body or TPS. Or vacuum leak. Cracked or broken vacuum line.

That sensor is not adjustable. It slides onto the throttle shaft and is screwed in place to the throttle body. Idle speed is controlled by the computer by adjusting air flow through the idle air control valve. If the idle is too high (you did not say) first clean the throttle body bore and plate, then if necessary remove the control valve, cleaning out the passage in the throttle body and carefully cleaning the valve itself, without turning the plunger. If that does not help, you will need to do electrical testing on that and other components to find out what's going on as well as checking all vacuum hoses attached to the engine for cracks or leaks.

There is no carburetor on any of the 6 cylinder or 8 cylinder Jeep Grand Cherokees. They have Fuel Injection and a throttle body which looks like a carburetor scaled down.

---
Instructions on how to remove and replace the throttle body follow:

Throttle Body REMOVAL & INSTALLATION

1. Disconnect the negative battery cable.
2. Remove the vacuum hoses from upper bonnet, unfasten the retaining clips and remove the upper bonnet assembly.
3. Remove the lower bonnet retaining bolts and lower bonnet.
4. Remove the throttle cable and the return spring.
5. Disengage the wire harness connector from the injector.
6. Disengage the wire harness connector from the WOT switch, ISA motor and TPS.
7. Disconnect the fuel supply and return lines from the throttle body.
8. Tag and disengage the vacuum hoses from the throttle body assembly.
9. Disengage the potentiometer wire connector.
10. Loosen throttle body retaining bolts and remove throttle body assembly from the intake manifold. To install:
    
11. Clean the intake manifold and throttle body mating surfaces of old gasket material.
12. Install a new gasket and the throttle body assembly. Tighten the mounting bolts to 16 ft. lbs. (21 Nm).
13. Engage the potentiometer wire connector.
14. Engage the vacuum hoses to the throttle body.
15. Engage the fuel lines to the throttle body.
16. Engage the WOT switch, ISA motor, TPS, and injector electrical connections.
17. Install the return spring and throttle cable.
18. Install the lower bonnet and fasten the retainers.
19. Install the upper bonnet assembly, retaining clips and vacuum hoses.
20. Connect the negative battery cable.
21. Start the vehicle and check for fuel leaks. Fig. 1: Exploded view of the throttle body and related components
    

Make sure you replaced or did'nt break any vacuum lines. this is the main culprit for fast idle

You need to test the throttle position sensor and MAP sensor as well as test for vacuum leaks from manifold or lines. The idle control valve only does what the computer tells it to based on the info it receives. Hope you cleaned out the passages to the iac valve when you replaced it!

Check PCV valve and be sure it is not stuck open.  Check for vacuum leak at intake manifold.