Acceleration Lag, 25-30mph max

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Dec 21, 2014 | 12:29 PM

Will.A

Thread Starter

Newbie

Joined: Dec 2014

Posts: 3

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Model: Cherokee

Acceleration Lag, 25-30mph max

Hey Guys here's the skinny, 2004 WJ Grand Cherokee Laredo.
Acceleration cuts out at 25-30mph. Will not go any faster.

What codes i found and took care of are for...
1.Misfire on 3 and 6... Replaced coil and plugs
2.Catalytic converter bank faults.
All Cleared upon replacing coil and plugs.

Acceleration still will not pass 25-30mph. From what I had researched it's similar to "Limp Mode" but I have no codes showing from Key/Ignition method.

Other things I have done:
1. Tested coolant temp sensor at Thermostat, works correctly no faults unless unplugged.
2. Fuel Filter (in-line), New replaced last night.
3. Tested TPS, no jumps or dead spots in voltage.
4. Fuel pressure and throttle response good. In Neutral great throttle response.
5. O2 sensors pre and post Cats no codes.
6. Pulled O2 sensors to test Cats, no change, tested and codes came up for mis-read as sensors are working properly.
7. New radiator, after she popped a hole while in idle sitting in driveway. boiled over into reservoir.

Any other thoughts, as I have no way to check transmission codes. and no other Engine codes are showing?

Thank You in advance for the assistance, Im out of state and trying to make it home to my wife and kids for Christmas.

Kindest Regards,
Will

Last edited by Will.A; Dec 21, 2014 at 12:32 PM.

Dec 21, 2014 | 05:29 PM

fwlau

Newbie

Joined: Dec 2014

Posts: 3

Likes: 0

Model: Cherokee

This sounds similar to my problem that I made a thread on a couple days ago. My ECM is showing no codes but my car is very clearly in limp mode. The first thing my mechanic is trying is to swap the TCC solenoid and governor sensor as these are apparently common problems in the WJ. Other than that I have nothing to offer you but just wanted to let you know we're in a similar boat so if I find out something I will let you know.

Dec 22, 2014 | 09:06 AM

GUARDIAN

Member

Joined: Aug 2014

Posts: 159

Likes: 1

From: LAS VEGAS, NV

Year: 2004

Model: Grand Cherokee (WJ)

Engine: 4.0 I6

Had something similar happen last summer on my 04 wj, I think I replaced the tps (throttle position sensor).
MINE HAD NO PROBLEMS WITH VOLTAGE BUT WHEN WHEN WE CHECKED IT FOUND THAT IT WAS CRACKED AND NOT MAKING CONTACT PROPERLY. I didn't get any codes. All I know is that after it was changed I had no more issues.

Last edited by GUARDIAN; Dec 22, 2014 at 09:12 AM.

Dec 24, 2014 | 02:06 AM

dave1123

Old fart with a wrench

Joined: Nov 2010

Posts: 14,398

Likes: 740

From: Manlius, east of Syracuse, NY

Year: 2000 XJ Sport & WJ Laredo

Model: Grand Cherokee (WJ)

Engine: 4.0L

One other thing that comes to mind, plugged catalytic converter.

Dec 25, 2014 | 05:33 PM

Will.A

Thread Starter

Newbie

Joined: Dec 2014

Posts: 3

Likes: 0

Model: Cherokee

Resolution

So with all the trouble shooting. It turned out it definitely was a plugged cat. It was causing a temporary "limp in mode" once cleared it ran like a champ.