My 2009 xlt Ranger cruise control is irratic. When you first set speed it usually accelerates a further 5kph then settles back but tends to wander up and down a fair bit. Seems slow to react to hills etc ?

It is HVAC 1fuse #39 in the rear fuse block ,this powers the on/off switch for cruise control ! Fuse Block - Rear Beneath the left rear seat. What engine does it have ? 4.2 L or 5.3 l There is no vacuum involved in the operation of the cruise control ! Your vehicle has electronic throttle control .
Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions at vehicle speeds above 40 km/h (25 mph). Steep grades may cause variations in the selected vehicle speeds.
The following are the main components of the Cruise Control System:
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The powertrain control module (PCM)

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The On/Off switch

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The Resume/Accel switch

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The Set/Coast switch

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The TCC brake switch

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The stop lamp switch

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The throttle actuator control (TAC) motor

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The vehicle speed sensor

Cruise Control Engaged
The cruise control system will engage and adjust the vehicle speed based on the activation of the following cruise control switches:
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On/Off

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Resume/Accel.

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Set/Coast

The cruise control switches are located on the multifunction/turn signal lever.
The powertrain control module (PCM) monitors the signal circuits of the cruise control switches in order to determine when to capture and maintain the selected vehicle speed. The PCM uses the throttle actuator control (TAC) module motor in order to control the vehicle speed. For further information on the TAC System, refer to Throttle Actuator Control (TAC) System Description in Engine Controls - 4.2 L.
Ignition positive voltage is supplied from the 10 ampere HVAC 1 fuse to the cruise control switch via the ignition 3 voltage circuit. When the normally open cruise control On/Off switch is turned On, the switch closes and the PCM detects a high signal voltage on the cruise control on switch signal circuit. When the normally open Set/Coast switch is pressed, the switch closes and the PCM detects a high signal voltage on the cruise control set/coast switch signal circuit. To engage the cruise control system, turn the On/Off switch On and momentarily press the Set/Coast switch. The PCM will confirm that the cruise control enable criteria has been achieved. The PCM will engage the cruise control system and record the selected vehicle speed. The PCM sends a class 2 message to the instrument panel cluster in order to illuminate the cruise control indicator. Pressing the accelerator pedal, while the cruise control system is engaged, will allow the driver to override the cruise control system in order to accelerate the vehicle beyond the current set vehicle speed. When the accelerator pedal is released, the vehicle will decelerate and resume the current set vehicle speed. The driver can also override the current set vehicle speed via the Set/Coast switch and the Resume/Accel switch. When the cruise control system is engaged, pressing and holding the Set/Coast switch will allow the vehicle to decelerate from the current set vehicle speed without deactivating the cruise control system. When the Set/Coast switch is released, the PCM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the cruise control system is engaged, momentarily pressing the Set/Coast switch will allow the vehicle to decelerate at 1.6 km/h (1 mph) increments for each time that the Set/Coast is momentarily pressed, with a minimum vehicle speed of 37 km/h (23 mph). When the normally open Resume/Accel switch is activated, the switch closes and the PCM detects a high signal voltage on the cruise control resume/accel switch signal circuit. Activating and holding the Resume/Accel switch, when the cruise control system is engaged, will allow the vehicle to accelerate to a greater vehicle speed than the current set vehicle speed. When the Resume/Accel switch is released, the PCM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the cruise control system is engaged, momentarily activating the Resume/Accel switch will allow the vehicle to accelerate at 1.6 km/h (1 mph) increments for each time that the Resume/Accel switch is momentarily activated, with the maximum acceleration total of 16 km/h (10 mph) over the current set vehicle speed . Momentarily activating the Resume/Accel switch, after the cruise control system has been disengaged by pressing the brake pedal, will recall the previous set vehicle speed that is recorded in the PCM.

Bummer deal! This may be a way to tell you some tail lights are burnt out. Some cruise controls have a fuse in a second location.
The fuse is not in right or is blown. Check with a new fuse. Hope this helps. ...gc http://www.auto-tune-up-and-repair-options.com/

Cruise Control
Any given speed above approximately 22 mph (35 km/h) can be maintained with the cruise control by operating the lever.
-see photo

1. Accelerate and set: Lift lever briefly to set speed. Hold lever up to accelerate.
2. Decelerate and set:
   Depress lever briefly to set speed. Hold lever down to decelerate.
   Normally the vehicle is accelerated to the desired speed with the accelerator. Speed is set by briefly pushing
   the lever to position 1 or 2. The accelerator can be released. The speed can be increased (e.g. for passing)
   by using the accelerator. As soon as the accelerator is released, the previously set speed will be resumed automatically. If a set speed is to be increased or decreased slightly, e.g. to adapt to the traffic flow, hold lever in position 1 or 2 until the desired speed is reached, or briefly tip the control lever in the appropriate direction for increases or decreases in 0.6 mph (1 km/h) increments. When the lever is released, the newly set speed remains.
3. Canceling

To cancel the cruise control, briefly push lever to position 3.
When you step on the brake or the vehicle speed drops below approx. 22 rnph (35 km/h), for example when driving upgrade, the cruise control will be canceled.
4. Resume
If the lever is briefly pushed to position 4 when driving at a speed exceeding approx. 22 mph (35 km/h), the vehicle resumes the speed which was set prior to the cancellation of the cruise control. The last memorized speed is canceled when the key in the steering lock is turned to position 1 or 0.
Note:
If the engine does not brake the vehicle sufficiently while driving on a downgrade, the speed you set on the cruise control may be exceeded and you may have to step on the brake pedal to slow down.
As soon as the grade eases, the cruise controlled speed will again be maintained as long as the brakes were not previously applied, or the lever may be used to resume the previously set speed if the brakes were applied.


http://www.benzworld.org/forums/attachments/w202-c36-c43/153145d1197313761-pdf-owners-manual-w202-1995-2000-1999-c280_owners_manual.pdf

Once you have turned your cruise control on accelerate to desired speed press SET button on right hand side of steering wheel before lifting foot from accelerator, then remove foot from accelerator. pushing RESUME button will deactivate cruise control without turning it off. Then when clear of traffic push resume again to activate cruise control. It will automatically resume to previous set speed.

Ok. I'll give you my best guess, although I am not a Dodge Stratus expert. Based upon your description of the problem, I am to assume that the vehicle has problems accelerating up to speed, but once there, cruises ok unless you are going uphill or need to accelerate quickly, then power falls off rapidly and acceleration returns very slowly. If that is accurate, I would suspect the EGR valve. This is because at ihighway cruising speeds the EGR valve is pretty much wide open, letting exhaust gases back into the intake. When you need to accelerate, pressing the accelerator results in intake vacuum drop. This is partially compensated for by closing the EGR valve. If the EGR fails to close or sticks partway open, the exhaust gases will lower intake vacuum even further, and rob engine power. This can also cause the onboard computer to force a downshift to the transmission, as vacuum sensors are used to determine engine loading and the need to reduce gearing. In addition, a partially open EGR valve can cause erratic idle as it affects static intake vacuum (EGR is normally closed at idle) and the onboard computer must continually compensate, resulting is unstable idling.

Most cruise controls are designed to disengage when you press the brake pedal. I always mention this first because people tend to try to press the clutch pedal while the cruise control is engaged and this startles them when the engine revs up all the way...

Anyway, to use your cruise control:

1) Press the Cruise control button to on.
2) Drive up to the speed you need to go.
3) Press the "Set/Coast" button.
4) let go of the accelerator pedal

If the cruise control system is operating correctly, your vehicle will continue to travel at the same speed until you either press the brake pedal or you cancel the cruise setting with the cancel button of the cruise control.

Remember: Your civic is not equiped with a radar system for your cruise control, so if you are aproaching an intersection or traffic in front of you, do not expect the car to know it needs to stop. Also, cruise control only operates the accelerator pedal i your car, it is not autopilot, so it will not steer your car for you.

(you think it sounds silly that I am writing this? You should see my friend's car... He thought Cruise control was like autopilot, so he smashed his brand new civic into a tree...)

Happy Motoring!

p 1780 tcs

check your vss on your tranny

All Toyota auto trans cars downshift when descending a hill when you tap the brake. This is called "Downhill Shift Logic"; what this is for is to eliminate the double shift when you come to the bottom of a hill and then accelerate. Normal condition. Usually happens above 38 MPH.
Also: The cruise will accelerate when going uphill. Normal condition.Plus: The cruise will not disengage back to the set MPH after you top the hill. Toyota recommends to disengage the cruise when encountering steep terrain.