Hey All,

Im not sure if this is the right place, so feel free to correct me. Im hoping someone can save me, as this is my only vehicle.

Vehicle
2000 Cherokee XJ, 2 Door, 4.0, Automatic, 4WD. 106,000

Problem
Very rough idle, 750 RPM, no stalling.
Extremly rough at, or around 1500 RPM, while in 3rd, 70 km/h (I believe its 3rd)

Here is what I have tried

1. Removed and cleaned throttle body, new gasket
2. Removed and Cleaned Air Idle Control Valve, new gasket
3. New tank of premium gasoline, and a can of seafoam in the tank, 5oz in the oil
4. Oil Change
5. Reset ECU twice
6. Reset Throttle cables
7. Confirmed Transmission fluid is good
8. Checked all fuses and air filter
9. Had Battery Load tested
10. Checked and cleaned grounds
*11. Replaced CPS

*** just recalled that it did run out of gas about one week prior to these issues starting***
***horn also stopped working around the same time***


I am not a mechanic, and do not have access to a mechanic (just a Walmart nearby). I have a socket set, and no money, but am willing to try anything.

Any help or feedback would be amazing.

Thanks

 

Is your check engine light on? Even if it's not, can you get any codes out of the ODB2 system?

The very first thing you should do, and it's the advice that you'll always get before doing anything else, is to go through and check and clean your grounds and battery cables and make sure everything is tight. By "check and clean" that means take it apart, make sure it's bright and shiny metal on the cable and where it touches the body or engine and reconnect it (with a little bit of dielectric grease if you want).

 

Sorry, just edited the original post, no codes according to my OBDII reader, and the check engine light is off.

 

Check the grounds - it's free, fairly easy and needs to be done before you can even think about starting to diagnose components.

Don't forget the one in the trunk behind the driver's side trim panel.

When you're done with that, you probably want to check your fuel pressure. I've heard folks north of the border don't have the plentiful loaner tool programs we have in the states, but check around and see if you can find a place to loan you a tester for free. (Assuming you don't own one, of course.)

 

Checked all the grounds. took them out, scrubbed with a nylon brush and some electric connection cleaner. They all looked good, and look better now.

 

okay, after much searching, and phone calls, and reading of manuals and such, I think i have it narrowed down to one of three. In no particular order...

1. Engine and Transmission Mounts
2. O2 Sensors
3. Fuel Pump

Trouble is, they are all pretty expensive. Any information on how to check these items, or other information would be amazing.

 

Rough idle is not typically associated with engine and trans mounts (vibrations and clunking yes, rough idle no).

O2 sensors and fuel pumps are certainly possibilities for this type of symptom. Though it is much more common for it to the be o2 sensors than the fuel pump.

When you start the vehicle from dead-cold (sitting overnight) does it idle well for a minute or two, then start to get rough after that?

 

Yeah, the only way i was thinking mounts was the shaking, and maybe that caused something... dunno. I will move that to the bottom of the list.

I am not sure if it idles well. It sits around 1,000 and is louder and slightly less vibrations. Then it will drop to 700ish, and shake more. So, maybe it runs a bit better at first.

 

So, here is a video before replacing the CPS, but after all of the other work.This Video is from this morning. The severity of the shaking and loudest of the idle are hard to pick up in the video, just imagine it is 5x worse than the video, and that brings you closer to reality.

 

Once I got the CPS out, it was registering an OHMS resistance between 17-25. I bought a new one with infinite resistance, and installed this morning. Took it for a 30-40 minute drive along the usual routes. Now I am getting error codes for cylinder 3 and 4 misfires and flashing check engine light or steady check engine light. Any ideas?

Another symptom to note is that at 60-70 Km/H, and 1,200 - 1,700 RPM there is extremely violent shaking. If I try to accelerate it is very slow, but will eventually get through, then the shaking stops. The same thing happens if I slow down until it gears down.

 

You might check the coil pack and the associated wiring. I'd replace the O2 sensor(s) and make sure their wiring is good as well.

 

 

I think the coil and wiring is the more likely issue - I'd start there. At least it costs nothing but some of your time to check the wiring.

If you have a crack in the manifold, you usually know it because the engine is very loud. You can take it to an exhaust shop and have them do some thorough testing using their fancy equipment, but it will probably cost $100 to do so.

 

Some new info, found out my cousins husbands dad has a shop. Dropped it off, he had it for two weeks....

New Ignition rail (coil)
New Spark Plugs
Replaced a few vacuum lines, not sure which ones
New battery
New O-Rings on Fuel injectors
New Map(?) Sensor
New Throttle Position Sensor
Cleaned Throttle Body (Again)
Sea Foam in tank and engine (Again)
Added an in line fuel filter
Coolant Flush and Replace
Reset ECU
Driven for 100 Kms

Charged me $900 CND.... he didn't quote me that, and because of the damn family ties and **** theres not much I can do about that. Just want to move forward and get a resolution.

Did not solve a damn thing. Last day, he told me he was still getting misfires on 3 and 4, did a compression check, said no compression. Told me i need a new motor. Gave it back to me. Runs the same as before, same issues, maybe a minor difference but I cannot tell because I have had it for two weeks. Im pretty distraught right now. I didn't have that money to spend, and it didn't solve my problems...... what now? ****. Im so defeated right now.

*** just recalled that it did run out of gas about one week prior to these issues starting***
***horn also stopped working around the same time***

 

It sounds a little like a failing CPS that was replaced with a very low quality CPS.

Can you tell us about the CPS you purchased? Do you have a link to the product?