Eruck

Hi Everyone!

I have a 2001 Jeep Cherokee Sport and I have been having this problem with my Jeep for years and I can never figure out what is wrong with it. I took it to different car places to see if they can figure out what the issue is but they can't seem to find anything. Basically it has to do something with my acceleration. What is will typically do, when I am idle or driving really slow, my tends to rumble or shake really hard, sometimes hard enough where it will kill my engine. The bad part is once it does that it will delay my acceleration whenever I need to go, I'll push on the pedal and it won't actually go till like 5 seconds after I pressed the pedal. Plus, sometimes when it does that delay, it will act like it is neutral, it will rev up my engine but it will sound very weak and louder than usual and then it somehow puts itself back into "drive" and will continue to accelerate the speed but it will do this for a while. Nothing seems to cause this from my knowledge, it just does it on his own at random times. What I have noticed is that it does it more often when it hot outside, which makes me think the heat has some affect to the engine or whatever it is caused. I really hope I can get some answer to get my car fixed, I love this car so much and I would do whatever to make it safe again. Thank you for reading this and I hope you have an awesome day!

Best,
Elijah

EZEARL

WELCOME

Any code #'s?

Tony the Liger

I had a vehicle once that did something very similar. Turned out to be an issue with the fuel line.

fb97xj1

Check for codes, even if the CEL is off. It will [usually] still store codes if there is a problem, but not always. Check the transmission fluid level and condition, fuel pressure, and for any possible vacuum leaks. When was its last tuneup? Could be anything wrong with it, and more than one problem.

Eruck

Tony - I thought about that too but what makes me confuse about that is if it has to do something about the fuel line, how am I still getting the fuel? Like it will still rev up my engine but it will sound "hallow" but it is still getting the fuel.

Ezearl - I don't have any codes with me at the moment, I am planning to get some soon though.

fb97xj1 - I will need to check for codes for sure, any codes specifically? I did a transmission flush and a radiator flush and a fuel flush as well. Every fluid I have in the car right now are new and cleaned out and it still does the issue for some odd reason. Plus, I did my last tune up a year ago and I remember once I got that done, it still did the acceleration problem. But we did find that there were 2 spark plugs not firing, so we fixed that but there weren't any other problems.

I also talked with my Uncle who is knowledgeable with cars, and he believes that it has to do something with the computer that is in the engine, do you think that could be the case? Because what happens sometimes when that issues start to occur, I turn off my car and turn it back on again, and it will go away. This has been an issue for years and just recently it has been getting worse I hope I can figure something out. Thank you all for you help, you guys rock! Let me know if there is anything else you would like to know, thank you!

Best,
Elijah

BlueRidgeMark

Many auto parts stores will pull codes for free. That's a good place to start. Get them pulled and post them here, and we'll see.

How's your fuel economy?

BTW, "it's the computer" is thrown around a lot. It can be, but that's not the first place to look.

Eruck

Hi Everyone!

I went to my local Autozone store and I found out a couple of things. First is that they found a code that there was something wrong with the O2 Sensor. The error code is: P0152. There is also another code that is related to the EVAP which is the Fuel Vapor, error code: P0455. So it makes me think that with the issue that I am experiencing, it could be linked with one or both of these issues. What do you guys think?? Let me know!

Best,
Elijah

extrashaky

First off, if you're going to drive a teenaged Jeep, get yourself an OBDII scan tool that can read and clear codes. Alternately you can use your phone as a scan tool by getting a bluetooth OBDII adapter and the Torque app (Android) or a wifi OBDII adapter and DashCommand (Iphone). I use the Torque app myself, and it's quite good. That way you can read and clear codes yourself. You'll need it again in the future, I'm fairly certain.

The first code is for high voltage from your bank 2 upstream O2 sensor, which can definitely affect the fuel mixture and change way the motor runs. Since it's the code for bank 2, I'm guessing you have four O2 sensors. Go ahead and replace both upstream sensors, since if one has gone, the other isn't far behind. The upstream sensors are the ones in your exhaust manifolds, up above the small catalytic converters in your engine bay. Buy NTK sensors with the OEM connectors.

Your downstream sensors may also be on their last legs, and the shock of the new sensors may push them over the edge also. However, they don't drastically affect the way it runs, so you can try just replacing the upstream sensors first, or you can just go ahead and replace all four and get it over with.

The other code means there's a vacuum leak in your evaporative emissions system. I don't think that usually causes any issues in the way it runs. It primarily keeps you from being able to pass emissions testing if you live in a nanny state with inspections, and it may make your evap purge solenoid tick louder than usual. You'll want to try to track down that leak eventually and fix it, so that the code won't cause confusion with other issues you may have.

Also, if your check engine light wasn't on, these may have been pending codes, in which an issue exists but it hasn't been consistent enough to cause the light to come on. However, if they were full codes, but your check engine light didn't light up on the dash, you need to make sure that light is working. Does it light up when you first turn the vehicle on?

A number of things could be causing you to have low fuel pressure, which could cause misfires and rough idle. If the O2 sensors don't fix your problem, you can "borrow" a fuel pressure test kit from Auto Zone and check to see if you're getting the correct pressure. It's very easy. There's a schrader valve on the fuel rail, and you just screw the fuel pressure gauge onto it, crank the Jeep and read the pressure. Yours should have 49 psi plus or minus a few pounds while running.

Usually low fuel pressure would give you a misfire code, so I would still start with the O2 sensors before doing anything else.