2003 grand cherokee shutter...

[jugdish35]

hello all, i have a problem with my 2003 grand , when at highway speed it shutters and jumps or bucks, i looked at the i.p. when this is happening and the speedo needle bounces all around . no other needles move . this problem started yesterday and it is intermittent, i can actually feel the jeep decelerate when this is happening .. has anyone experienced this sort of problem or have any ideas . any help is greatly appreciated .


thanks , jody

4x4 4.0 liter

 

[SteelHeadz]

Is the SES lamp on when it happens?. A shudder or bucking could either be created by the engine or transmission. At what speed does this occur and is there any other symptoms?. If this is an electrical related issue, i would say that the speed sensor is failing.
The Input Speed Sensor provides information on how fast the input shaft is rotating. As the teeth of the input clutch hub pass by the sensor coil, an AC voltage is generated and sent to the TCM. The TCM interprets this information as input shaft rpm.
The Output Speed Sensor generates an AC signal in a similar fashion, though its coil is excited by rotation of the rear planetary carrier lugs. The TCM interprets this information as output shaft rpm.
The TCM compares the input and output speed signals to determine the following:

• Transmission gear ratio
• Speed ratio error detection
• CVI calculation

The TCM also compares the input speed signal and the engine speed signal to determine the following:

• Torque converter clutch slippage
• Torque converter element speed ratio

With this in mind , if either of the sensors fails, the TCM will not be able to tell the actual output RPM and will probbably have some shift issues and or lock and unlock of the torque converter.

 

[jugdish35]

steel, no ses light , it mostly happens at highway speeds of 60--- 70 mph . thanks , jody

 

[SteelHeadz]

It's possible that the transmission is hunting for a higher or lower gear or a torque converter switching from a lockup to unlock back and forth. Is this more like what it feels like. It's hard to tell with the description of the symptom rather than actually experiencing the symptom.

 

[jugdish35]

steel, where are these sensors located .... are they on the drivers side of the transmission and are they the plastic screw in type? jody

 

[freddie5]

unlikely to be the speed sensors as you should get limp mode - question to answer : is the problem only experienced after 02 sensors and other temp controlled sensors go in to closed circuit mode? i.e after engine warm-up has completed - or put it another way if you get to that speed (where the stuttering happens usually) before complete engine warm-up does the problem occur or not?

 

[jugdish35]

engine is at operating temp., changed the speed sensor anyway because it was only 19.00 dollars . and the end of the sensor has much goop and TINY METAL SHARDS . TOOK A PIC OF SENSOR BUT DONT KNOW HOW TO LOAD TO THIS THREAD .

 

[jugdish35]

picture of sensor is in my photos, its the best i could do . not to computer savy .

 

[SteelHeadz]

I wasn't going to suggest a replacement, but rather suggest checking the connectors and wirings. Did it make a difference on the symptom?

 

[jugdish35]

I wasn't going to suggest a replacement, but rather suggest checking the connectors and wirings. Did it make a difference on the symptom?

no, but get this , i had it idleing today and the ground strap that attaches to the stud on the valvecover and to the fire wall, well i pulled on it and it would shut the motor down . did it a few times just to be sure it wasnt a freak thing . the actual stud that the g strap is connected to was loose . so i tightened it up and when i pull on it the motor stays running . i will let you know if it actually cured the problem tomorrow when i drive to and from work . oh and i work at jefferson north assembly plant , home of the grand cherokee and commander . wish me luck and thanks for your input . jody


any thoughts???????? or comments are appreciated .

 

[freddie5]

no, but get this , i had it idleing today and the ground strap that attaches to the stud on the valvecover and to the fire wall, well i pulled on it and it would shut the motor down . did it a few times just to be sure it wasnt a freak thing . the actual stud that the g strap is connected to was loose . so i tightened it up and when i pull on it the motor stays running . i will let you know if it actually cured the problem tomorrow when i drive to and from work . oh and i work at jefferson north assembly plant , home of the grand cherokee and commander . wish me luck and thanks for your input . jody


any thoughts???????? or comments are appreciated .

_______________________


it just confirms that whenever a problem arises first priority is to thoroughly check all connections/wiring for something thats come loose

 

[jugdish35]

welp drive to work went well, drive home not so well, so much for loose ground strap theory . i even loosened up the strap when i got home and it stayed running this time . how about a catalytic converter thats on its way out . now when i throttle it up at highway speeds it has a light backfire . but still no codes... i did change my plugs about a month ago , so i checked all the connections around the coil area that i may have disturbed ,.. very confused ....