Part throttle Vac Issue

[Mattgfx]

Update

great news guys i installed the used Throttle body and the car runs perfect!!!! No more hesitation!!!! The car is completely smooth!!! , it feels like a new car...

[Mattgfx]

update 3 days later

Car is still running great and feels completely different! responsive and smooth like an s4 should be

[BITRBO]

Update

great news guys i installed the used Throttle body and the car runs perfect!!!! No more hesitation!!!! The car is completely smooth!!! , it feels like a new car...

update 3 days later

Car is still running great and feels completely different! responsive and smooth like an s4 should be

Holy shit balls dude!! Great to hear Hopefully we found our answer after all this effort (*fingers crossed*)...

Now I just have to find me some used TB love

[rune]

Holy shit balls dude!! Great to hear Hopefully we found our answer after all this effort (*fingers crossed*)...

Now I just have to find me some used TB love

Hmm, i have this RPM 200+/- variation when driving and steady throttle ,just in the startup fase and goes away when warm. Do you think this can be related to the Throttle body ?
i have a 2006 A4 2.0Tfsi Tiptronic. No codes.

SOLUTION:

My problem is solved, changing my torque converter.

[BITRBO]

Not really sure, but from the sounds of it no... This problem exists when the car is cold OR hot; doesn't really matter. Its also not a problem with engine speed, but rather vacuum. Not sure if you realize it, but you're also talking about two completely different engines... Might wanna try the B6A4 section to see if someone has a solution

Uggg... I still have the used TB I bought last fall but haven't had time to install it yet

[WillRaceForBeer]

Bump! Has anyone had any further success with the TB? Has anyone cleaned their TB with positive results?

I have suffered from this problem for the past 3 summers. Seems to go away completely by early winter. Right now it's acting up worse than usual. I tend to only wot or decelerating lately.... cruising is not an option. what a PITA!

[BITRBO]

Sadly, I still haven't had time to swap mine out and my car is acting the exact same way.... Chugging/surging during partial throttle cruising (10 in.Hg. of VAC or more), and fine at 0 in.Hg. of VAC or less (i.e. boost).

I have to either accelerate or coast when I have people in the car - it's so embarrassing

[Timtheguru]

After installing new intercoolers last night I started having this problem, it was too late to try and diagnose and probably wasn't related to the intercoolers. I fixed it today by doing a throttle body alignment, doesn't surge vacuum at all now. Just leave the key in the on position for about 30-45 seconds and then start the car. I wonder if this is caused by turning the key to the on position for about 20 seconds and then starting the car before it completes the alignment. Just some thoughts.

[WillRaceForBeer]

Pulled negative battery cable and forced a tba (left key in on position for 2 min with motor off). Car was smooth for about 5 minutes, then started fluctuating at cruise again. Going to perform a tba with vag-com when I get home, but I expect the same result. I started getting a code "17966 throttle actuator electronic malfunction" it's intermittent for now. I'm going to begin exporing tb replacement options.

[BITRBO]

Pulled negative battery cable and forced a tba (left key in on position for 2 min with motor off). Car was smooth for about 5 minutes, then started fluctuating at cruise again. Going to perform a tba with vag-com when I get home, but I expect the same result. I started getting a code "17966 throttle actuator electronic malfunction" it's intermittent for now. I'm going to begin exporing tb replacement options.

Yeah, the TB re-alignment only helps for a few miles/days, if at all... I've had the same codes which has be convinced its a faulty TB.

[Yuckie]

Having similar issue: Light rhythmic hesitation/stuttering under partial throttle, gone at WOT, or if I'm over 7-8 PSI while partial throttle. Difference for me being my boost gauge doesn't fluctuate at all (new style AWE gauge). I've always thought it was my shitty OTS GIAC tune, but now this thread has me questioning that. I'm going to try the TB alignment tonight to see if that changes anything and will report back.

Really appreciate all of the information you guys have posted on this!

[mys4.org]

I too am having the problem. I got a used TB and swapped it in and still the problem is there. My friend and I did discovered a vac leak around one of my injectors... likely the injector o-ring needs to be replaced. I have a feeling that is the problem but it's just a pain to find the time to replace it.

[BITRBO]

Bump for some good news... Problem solved!

So my car has gotten progressive worse lately (or maybe just cause I've been driving it more often), and I finally got sick and tired of it... So I swapped out my stock TB last night for the used one I bought last fall, and O-M-G!! I forgot what it was like to drive this car and not be every single mile in Miami stop & go traffic. I've tried so many things over the past few years and thought there was no hope to ever fixing this problem, until Mattgfx and AudiSportB5S4 found the problem by logging:

http://www.audizine.com/forum/showth...=1#post5526634

Thanks again guys!

[034Motorsport]

Bump for some good news... Problem solved!

So my car has gotten progressive worse lately (or maybe just cause I've been driving it more often), and I finally got sick and tired of it... So I swapped out my stock TB last night for the used one I bought last fall, and O-M-G!! I forgot what it was like to drive this car and not be every single mile in Miami stop & go traffic. I've tried so many things over the past few years and thought there was no hope to ever fixing this problem, until Mattgfx and AudiSportB5S4 found the problem by logging:

http://www.audizine.com/forum/showth...=1#post5526634

Thanks again guys!

Wow, really? You remember how I was experiencing this as well?

It went away for a long time, but now has come back with my 2.8L GT build all of a sudden. However, I'm not logging that much difference from accel position to plate angle. I'm about to throw on my RS4 TB so maybe that will do something.

Congrats though; I know you had that problem as long as I did.

[BITRBO]

Wow, really? You remember how I was experiencing this as well?

It went away for a long time, but now has come back with my 2.8L GT build all of a sudden. However, I'm not logging that much difference from accel position to plate angle. I'm about to throw on my RS4 TB so maybe that will do something.

Congrats though; I know you had that problem as long as I did.

Well, I'm hoping I didn't jinx it by posting this, but so far so good... If this didn't work I was going to test the injectors next, cause apparently people have said that leaky O-rings cause similar issues. Worth a squirt or two w/ some starter-fluid if anything!

GL

[mys4.org]

Well as mention a year ago I did replace my TB and still the issue existing. Unless I just happen to get another used one with the same issue. I've also replace my EGT sensors, since there were bad and hoping that would help.... but no luck. The only thing wrong with my car at this time is my rear (Sensor2) O2 sensors are bad and I have a leak in the Evap purge valve.

I've had this issue since I got my S4 back in November of '07. As mentioned before this issue is not as bad when running a stock tune, but still is present. I've had both a APR and MTM tune on two different ECU so I can eliminate that being the issue. I hate throwing parts at my car but unless anyone else has had any luck I guess it's just a live with it issue.