[Mshell.d]

Hello, I've had my 2007 TSX for a year now. Have noticed stuttering/hesitation at around 2/3 RPM while driving. Has trouble shifting it seems, especially downshifting. The stuttering seems to be getting worse. I've read other threads, but was on the TL thread before realizing I should be on this one. On the other thread someone mentioned Dr. Tranny Shudder Fix--can it be used for TSX for the problem? I recently just had a huge issue with the VSA system--check engine light came on--check emissions immediately. Felt like car was going to shut down. Code reader mentioned throttle pedal sensor problem. Took it to a service station--light went out, reader read no issues! Took car back after they tried to instigate the problem for days to no result. A few weeks later battery light came on--next morning, battery dead. Bought new battery and replaced it. All seemed fine for two days. Driving home at lunch VSA system started freaking out--engine light, battery light, rpms and mph started going crazy, throttle being strange--CAR shut down completely on me while driving--thankfully I pulled over to the side before total shut down. Turns out alternator was bad--drained new battery almost overnight. Many $$ later and new alternator and new battery all seems fine except now for the shudder/stutter/hesitation. Please tell me I don't need a new transmission! Any help is truly appreciated.
Michele

 

[Robardin]

Stuttering/hesitation that "snaps back" to normal sounds more like a fuel delivery issue.

Do you hear a whining noise when this happens? Failing fuel pump?

 

[Mshell.d]

Hi. thanks for responding. I do not hear a whining noise at all.

 

[shandalo]

Look up APP sensor threads. The sensor may be faulty or it may just be an issue with the throttle cable having too much slack. You can tighten the cable until it has minimal deflection before starting to move the throttle rotor. This worked for many, including myself. If that doesn't fix it you may need to replace the APP sensor, but first it would try tightening the cable and cleaning the throttle body.
Also, when I had this issue the best way I found to "instigate" it would be to try to hold the rpm at a set value in the mid-range, or 4-5k rpm. Recently did this and could consistently get the car to throw the code. While attempting to hold the car at 4500rpm I got throttle input from APP sensor looked like this:

After tightening cable and cleaning the TB it looks like this:

 

[Robardin]

What app is that that you've got there displaying APP sensor output? Very cool.

I also had some "engine surging" issues that a TB cleaning seems to have fixed, along with a replacement of the engine belt tensioner. Those were not "throttle dying" problems though, more the opposite (sudden spikes in RPM when I thought I was being even on the throttle, not "stuttering" as the OP described, which I read as bogging down).

Now that you mention it, this was not long after my alternator also needed replacing. Whether or not it was related to the alternator dying, it was warped. I figured that was because the previous owner had run aftermarket lightweight pulleys that cause all sorts of belt problems for me until I restored it all to OEM.

 

[shandalo]

The app pictured is Torque pro. I use it along with a Bluetooth OBDII adapter. App is $5 IIRC, adapters are now $10-$20 I think.
Torque provides me with the ability to check and clear CELs, as well as see real-time-ish diagnostics. "Ish" because there is some inherent latency. All in all a very useful tool for knowing what is going on with your engine. I've been using it for nearly a decade. It is also capable of using your phone sensors for altitude, gps, etc, data logging, timing your 0-60, 1/4mile, calculated HP/TQ or whatever.
Here's the home screens for each of my vehicles:
TSX

MR2