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sprinkles08, ASE Certified Technician
Category: Jeep
Satisfied Customers: 22690
Experience:  Chrysler/Dodge/Jeep Master Certified, ASE Master and Advanced Certified, Trans and Hybrid Specialist
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Grand Cherokee Laredo: , the rpm jumps all the time

Customer Question

Hi, the rpm jumps all the time
Submitted: 2 years ago.
Category: Jeep
Expert:  sprinkles08 replied 2 years ago.
Hello and welcome to JustAnswer!
I'm assuming either the idle is fluctuating or RPM's fluctuate on their own while driving at a steady speed.
If you have a 3.7 or 4.7 then the most likely cause would be an erratic signal from the throttle position sensor. When a TPS gets worn it can start to create voltage fluctuations in it's signal. The powertrain control module will see the fluctuations and think the throttle is opening so RPM's will follow.