1990 Jeep Laredo Jeep bad jerking

Tiny
BRATTMAN1980
  • MEMBER
  • 1990 JEEP GRAND CHEROKEE LAREDO
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 153,000 MILES
My jeep drives fine when im easy on the gas peddle but as soon as I hit the gas my rear end jerks real bad back in forth it will stop once I let the gas go please any ideas
Wednesday, January 28th, 2009 AT 2:31 AM

7 Replies

Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok I would like you to test the TPS to see if it working properly and also when was the last time you checked the cap, rotor, and wires and how old are the plugs? Do you have a digital multi meter to test the tps with? Let me know what you can and we will go from there.
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Wednesday, January 28th, 2009 AT 10:38 AM
Tiny
BRATTMAN1980
  • MEMBER
  • 5 POSTS
Ok what is the tps and where is it at and how do I test it
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Wednesday, January 28th, 2009 AT 11:31 AM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok the TPS is the throttle position sensor, it tells the computer how far the throttle is open. Now it is on the throttle body on the other side of the throttle cable. Before I tell you how to test it I need to know if you have a digital multi meter as that is needed to do this. Here is a pic of a TPS.


https://www.2carpros.com/forum/automotive_pictures/249564_93841_1.jpg

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Thursday, January 29th, 2009 AT 10:30 AM
Tiny
BRATTMAN1980
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  • 5 POSTS
Yes I have a multi meter
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Thursday, January 29th, 2009 AT 12:36 PM
Tiny
RACEFAN966
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Ok first you need to find the connector with the three wires and the blue one that goes to a yellow and green wire this is your signal wire. Now back probe this wire with a paper clip or something that will go down in the connector without disconnecting the connector. Possitive of the multi meter to the tps wire and the black to ground set it on the 20 volt setting. Now turn key on engine off and you should read.8 volts or close to and now slowly and steadly open the throttle to wide open and it should read 4.6 to 5 volts wide open, while opening the throttle what the voltage it should steadly increase with no drops or glitches. Get back to me with what you find and we will go from there.
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Friday, January 30th, 2009 AT 10:48 AM
Tiny
BRATTMAN1980
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  • 5 POSTS
When I was testing with the throttle open it went to 9 volts but never stopped or skipped
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Friday, January 30th, 2009 AT 12:39 PM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Thats not good. It should not reach higher then 5 volts. Now one of the wires is ground and the other should be 5 volts in. Check the other two and let me know what you find.
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Friday, January 30th, 2009 AT 10:52 PM

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