Hi,

I’m trying to troubleshoot the cause of intermittent shuddering while accelerating.

Here are some details:

80k miles with regular oil changes
No check engine light, No faults found using the OBD2 reader from my local auto parts store.
Idles fine
Engine revs up and down fine
Shudders at RPMs in all gears with reduced power.
Shudders on a cold or hot engine.
While not shuddering there’s plenty of power with smooth acceleration.
Shuddering when it happens varies in intensity.

Going into neutral and coasting with foot off the pedal (to allow the throttle plate to close) before going into gear sometimes clears the issue.

No clicking sounds while turning the car - doesn’t appear to be a CV joint.


What I’ve done so far:

Cleaned out the throttle body and completed the idle relearn procedure to no avail.
The throttle plate has a little play but returns to position as shown in the service manual.

My current hypothesis is a faulty throttle position sensor and/or a loose plate axle is causing the intermittent shuddering due to a mismatch between what the computer reads and the actual position.

As far as I can tell these sensors are integrated in the throttle body and cannot be serviced, right? I’m guessing the sensor is a potentiometer that might just need cleaning with contact cleaner….

Any help is appreciated. I am thinking of replacing the throttle body but will try to repair the sensor first if possible and see if that fixes the shuddering.

I have tools and a DMM.

 

Play? It should not have play.

 

Thanks, Yes it wiggles a bit, as if the gear teeth are worn down. I am new to electronic throttle bodies. Will double check and upload a video soon. could the throttle plate play cause the shuddering?

 

It's bad and may be the cause of the problem.

 

okay here’s the video just in case the wiggle/play I’m describing is expected.

Also, I removed the battery cables and did some spot resistance checking on the throttle body pins. I couldn’t find the circuit diagram in the service manual. The resistance across pins 5 and 6 (where pins start with 1 on the left) is a few ohms and jumps while moving the plate.

Here's the link to the video.
https://drive.google.com/file/d/1b5z...ew?usp=sharing


found the diagram. As it turns out you need a torx security bit to take off the sensor cover.

 

Not sure if it's bad.

 

Thanks. It looks like the TP sensor cannot be serviced. At least I’ll have a brand new throttle body if that doesn’t fix the issue.

 

Let us know how it goes.

 

any ideas on what might be causing this intermittent shuddering issue?
any other… ideas

 

Let's see what the new TB does.