Engine hesitates or delays hard accelerations and the rpms go down then up

[McMuffinStuffer]

Hi, I have a 2001 Cherokee I bought. Automatic, 174k miles.

It's turned off on me sometimes when I'm in idle, I press the gas, the rpms go up but when they drop back down they can sometimes drop below 500/400 (depending on how I press the pedal) and the times it drops very low I see the dash lights dim and then that's when its turned off on me. Twice at a red light and once in park.

Here are the codes that I currently read:
P0123 - Throttle position sensor/accelerator position Pedal Circuit HIGH input
P0122 - Throttle position sensor/accelerator position Pedal Circuit LOW input
P0113 - Intake Air Temperature Sensor 1 Circuit High

I also have other similar/related symptom when driving. When Im driving and step on the gas, if I step on it with some force the rpms first lower a bit(maybe100-200) and cause a bit of shaking and then they rise. So it's like a hesitation or a delayed acceleration.

If I step on the gas lightly enough I can avoid the second issue but its still a problem.

The previous owner said the catalytic converter was bad and that he had the cat code for a couple months. Idk why my sensor doesnt read it.



As far as work done to it so far, I swapped the Air Temp sensor with one I know works from a cherokee that doesnt have that code. But it didnt change anything.

I also manually rose the 'gas lever' on the engine to make the rpms a little higher. It starts at 1k and lowers to 700ish and for the meantime that keeps it from turning off. But it seems like it also takes a little while longer to change gears.

The IAC and TPS were both changed in 2017.



Thanks so much for reading through all, If you have any tips or ideas about this please let me know. Thank you

 

[Unclewolverine]

Recently changed tps doesn't matter, I've had new ones go bad in a week. Really sound like a maybe a rubbed wire or poor battery connections. Check terminals and read tps with multimeter.

 

[McMuffinStuffer]

Thanks for the reply. I haven't used my multimeter much before. On which setting do I set it on to check the terminals? and thats to check the wires and tps terminals?

 

[Tim_MN]

Use the OBD-II Check Engine Light trouble codes to guide and focus your diagnostics.

Youtube is full of tutorials, BleepinJeep and ScannerDanner have diagnostic video's worth watching, and all you need from your multi-meter, is 12 volts testing, continuity to ground testing, and wire continuity from sensor to PCM testing.

In addition to testing and diagnositcs for the trouble codes, have the battery and alternator Load Tested, some of the symptoms strongly suggest low battery voltage.

 

[McMuffinStuffer]

Hi I just got a Throttle position sensor delivered. I also checked the battery voltage following a video guide and it seemed normal. After I changed the TPS the 2 TPS related codes went away as well as the other Air Intake Tempt one. Thank you guys for that.

I hadn't driven it much since but it feels good just at idle and normal enough driving.
One thing I did still notice is still one issues where at idle/park/stopped if i step on the gas the rpms go down a little bit and if you press the gass exactly when the rpm are low it'll still turn off. Though it does seem like its as bad as it used to be. Maybe just because the rpm have been manually adjusted by that lever.

 

[McMuffinStuffer]

Question, are there 1 or 2 Intake Air Temp sensors in the Jeep? I had swapped out one I saw from a video that is next to the throttle body but it looks like there is another just like it closer to the radiator that is angled.

 

[McMuffinStuffer]

Also the guy I bought it from said he had a catalytic converter code for about 9 months and he said that was something the jeep needed. I didn't catch that code but is it very possible that the cat is causing this sort of hesitation even if my sensor aint catching it?

 

[RCP Phx]

Question, are there 1 or 2 Intake Air Temp sensors in the Jeep? I had swapped out one I saw from a video that is next to the throttle body but it looks like there is another just like it closer to the radiator that is angled.

Only one AIT sensor.

 

[Tim_MN]

A faulty Coolant Temp Sensor (CTS) can acceleration cause issues, and not set a trouble code. The CTS can be tested.


First thing, reboot the PCM and delete any bad data from the faulty TPS.

Jeep 4.0L PCM Reset Procedure

-Disconnect the battery by removing the positive battery cable..
-Ground the positive cable for 30 seconds to engine block or A/C compressor to erase charge in the capacitors.
-Reconnect the positive cable to the battery.
-Turn the key to on but do not start.
-Turn the headlights on.
-Turn the headlights off.