Dusdangers08

As the title states this thread is about bucking/jerking that a few of us has experienced at low rpm (1500-3000)
I encountered this problem about a month ago. Its as if there is a dead zone in the gas pedal and would cause the car to buck as if were decelerating and acceleration on and off rapidly. having a K-pro i data logged the car during normal driving around town till the problem occurred which would only happen sometimes. the datalog showed that around 30% on the TPS it would fluctuate between 0% and 30% when the bucking would occur. My immediate thought was that the TPS was faulty. I bought a Blox TPS off amazon and did the the DIY found here on s2ki. Using a multimeter i set the voltage to .5 closed throttle and 4.5 at WOT. I made sure that the sensor was getting a constant 5.0 volts and also there were no dead spots when opening the throttle body which was also done on the original TPS which seemed to have checked out fine but since i bought a new one i figured id changing it anyways. Taking the car out for a drive after the problem persisted and i was stumped. My next thought was to changed the MAP sensor could be the problem as that was the cause of hesitation at High RPM. Even after changing the MAP sensor and using a cable tie to ensure the connection was good the bucking still happened. I finally decided to clean the throttle body, more specifically the TPS side. After removing the TPS i used carb cleaner to spray and clean where the TPS goes NOT THE TPS ITSELF. some gunk was flushed out and i checked for smooth operation while operating the throttle body by hand on the other end(drive by cable). After resembling everything the problem has been gone for two weeks already. hope this helps others as other threads on this topic has no solution that works. ill keep this updated in a few weeks if the problem came back or not

for those who don't like reading
symptoms: hesitation/jerking/bucking at low rpm
solutions that didn't work: replace TPS and MAP sensor and MAP whack
solution that worked: clean TPS side with carb cleaner

Midnightdennis

Have experienced the same issues and tried everything you mentioned except replacing the TPS sensor. What year is your S? AP1 or AP2?

Hfreak

I have recently had this problem with my 2006 and had a P2138 CEL, my problem was the APPS assembly. Been a few weeks since being replaced and drives as it should.

Dusdangers08

Dusdangers08

[left]yes the APPS could be the problem. However that would only pertain to dbw s2000s MY06+. Pre 2006 don’t have an APPS. Thanks for adding that for the dbw guys

Midnightdennis

I have an 06 as well. Did you also have the bucking issue at low speeds? For example, I would get the jerking/bucking after pulling out of the gas station in first and letting off the gas. Bucking wouldn't stop unless I shift to second, depress clutch pedal or give it gas.

I don't have any codes tho.

Hfreak

^^^ Mine was not that violent, just bucked while maintaining speed and like a hesitation but did get the code a few times. Good luck with the troubleshoot.