I drive a 2001 Cherokee. At times when I am driving and pull to a stop and go to accelerate again my engine will rev and the rpms will go up but i dont move. then it will catch and i lurch forward. This doesn't happen all of the time but enough. I tried changed my trans fluid and filter last weekend but it hasn't fixed anything.

I can't figure out what is going on does anyone have any suggestions? I could really use the help, thanks!

 

have you adjusted the kickdown cable?

 

Push the half moon button down and push the cable and boot all the way back in as far as it'll go. Once that is done, with the truck not running, push the gas pedal to the floor until you hear a click. Take it for a test drive and let me know if it helped.

 

Ill give that a try, thanks!

 

It still struggled after I tried this ^. Is there any chance it could be the TPS Sensor? Is there any other way to test the TPS other than an ohm meter?

 

it could be, but it's most likely the shift solenoid in the trans.
not very expensive and easy to do.

 

Assuming that you haven't seen a check engine light?

There are a few possibilities, but the throttle position sensor should be ruled in or out before moving onto other things. Here's more.
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The throttle position sensor is connected to the throttle shaft on the throttle body. It sends throttle valve angle information to the PCM. The PCM uses this information to determine how much fuel the engine needs. The TPS is really just a simple potentiometer with one end connected to 5 volts from the PCM and the other to ground. A third wire is connected to the PCM. As you move the accelerator pedal with your foot, the output of the TPS changes. At a closed throttle position, the output of the TPS is low, about a half a volt. As the throttle valve opens, the output increases so that, at wide open throttle, the output voltage should be above 3.9 volts. Testing can be performed with an electrical meter. Analog meter is best. You are looking for a smooth sweep of voltage throughout the entire throttle band. While slowly opening and closing the throttle, take note to the movement of the voltmeter needle. There should be a direct relationship between the needle motion to the motion of the throttle. If at anytime the needle moves abruptly or inconsistently with the movement of the throttle, the TPS is bad

You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.

The TPS is sensitive to heat, moisture and vibration leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following: -

NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics! It should be verified early in the troubleshooting process, when a transmission issue is suspected!

• Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".
• High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.
• Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.
• Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted accordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.
• Engine Misfire: A fault TPS can report values outside the denied acceptable range causing the ECU to incorrectly fuel the engine. This is noticeable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.

 

"• Engine Misfire: A fault TPS can report values outside the denied acceptable range causing the ECU to incorrectly fuel the engine. This is noticeable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage."

I don't have a check engine light on currently. But I had one or two months ago and it was for a cylinder misfire. Do you think it could be connected to TPS Sensor and everything else that is going wrong?

I think i might by an analog meter in the morning and test it.

 

I bought the meter yesterday and ran the test. The Sweep seemed smooth so I am not sure if it is the TPS sensor? However when i was driving to work this morning it started to run rough and i got a check engine light. I have never been so excited to see a check engine light! Hopefully this will give me some answers.

 

Yup, retrieve the code(s) and post the exact code numbers here (not just a description)

With OBD codes, the devil is in the details and interpretation is not straight forward.

 

Is the level of coolant in the reservoir bottle dropping?

 

@Kalali,
Yes it is actually, whats that mean?

 

I got the codes, they are:

P0123
and P0122

I bought a new TPS sensor, we will see if that helps. Any other thoughts?

 

Both of those codes are related to the throttle position sensor. Replacing it will very likely resolve your issue.

I'd soak the fasteners with some penetrating oil as they are often stubborn to remove; have had to cut them away.

Good luck and keep us updated!

 

I changed the TPS sensor and drove for about 30 minutes tonight. The engine runs smoother than it was this morning. However my initial problem of a delayed shift from neutral to 1st when i stop my Jeep is still happening. Any other ideas?