car loses power @4K+ rpm w/ no CEL???

[patman]

My S4 will sputter or lose power above 4K rpm & has no CEL then tries to drop or lower the rpm back down. As I try to give it more throttle 4K+ rpm, the car will hesitate forward with no power. Since i bought my Stg2 S4 4 months ago, everything runs great aside from the MAF & coolant sensor I just had to replaced 2 weeks ago. Any help or suggestions will be greatly appreciated.

[The_Jerbel]

Did you clear the codes from the bad MAF and CTS?

[patman]

yes my indie tech did.

[theboogieman1]

I had the same thing happening to me except if I let up while it was hesitating the whole car would clunk. Never found out what it was but I was thinking it was a boost leak somewhere because it felt the same as when my TBB was torn. Have you checked for leaks?

[RogueStatus]

you have a boost gauge? if not invest in one to watch for boost loss in case it is just a leak somewhere.

nothing else happening? battery level staying up,coolant and oil gauges reading fine?

best bet is to find (if you dont have) a VAG-com and do some logs or tests...

[torment]

Same thing happened to me and my TBB was toast.

[mholme]

Could be boost leak(tbb or elsewhere). Easy enough to pressure test.

[patman]

you have a boost gauge? if not invest in one to watch for boost loss in case it is just a leak somewhere.

nothing else happening? battery level staying up,coolant and oil gauges reading fine?

best bet is to find (if you dont have) a VAG-com and do some logs or tests...

no boost gauge yet, but will get one soon after this hichup. nothing else happened, everything else & gauges were all fine. 1st Audi/VW here so i guess gotta buy VAG-com soon too.

Same thing happened to me and my TBB was toast.

that might be it, if so i need to upgrade to the Samco ones.

Could be boost leak(tbb or elsewhere). Easy enough to pressure test.

thanks! I'll check the TBB & elsewhere.


Thanks everyone for help & guide! I wanted to ask here 1st becuz my indie tech i've been using for 10yrs+ usually works on Pcars, BMW, & Merc rarely on our Audis. Thanks again guys!

[Jurjen]

you have a boost gauge? if not invest in one to watch for boost loss in case it is just a leak somewhere.

A boost gauge won't show that you have a boost leak. I just replaced my TBB after similar hesitation problems, and according to the gauge, it builds boost exactly the same way - torn boot or not.


Just think how fast your turbos must be spinning to create 15psi (or whatever your car boosts too) when half the pressurized air is escaping somewhere *cringes*

You can physically check the TBB (If you don't have a pressure tester handy) , its pretty easy to get at after all.

[patman]

A boost gauge won't show that you have a boost leak. I just replaced my TBB after similar hesitation problems, and according to the gauge, it builds boost exactly the same way - torn boot or not.


Just think how fast your turbos must be spinning to create 15psi (or whatever your car boosts too) when half the pressurized air is escaping somewhere *cringes*

You can physically check the TBB (If you don't have a pressure tester handy) , its pretty easy to get at after all.

thanks! I ordered online last week the Samco TBB & F-tube w/ the AWE vent boost gauge already. Where's a good/cheap place to buy the pressure tester & VAG-com??

[RogueStatus]

[QUOTE=Jurjen;2652546]A boost gauge won't show that you have a boost leak. I just replaced my TBB after similar hesitation problems, and according to the gauge, it builds boost exactly the same way - torn boot or not.
QUOTE]


welp it showed me,and shows me all the time. when i have a leak somewhere itll show,boost doesnt build up properly and wont be where it should be regarding pounds of boost...


best bet for VAG is just buy it from ross-tech.com

[patman]

[QUOTE=EuroSteez;2653380]

A boost gauge won't show that you have a boost leak. I just replaced my TBB after similar hesitation problems, and according to the gauge, it builds boost exactly the same way - torn boot or not.
QUOTE]


welp it showed me,and shows me all the time. when i have a leak somewhere itll show,boost doesnt build up properly and wont be where it should be regarding pounds of boost...


best bet for VAG is just buy it from ross-tech.com

Thanks Eurosteez!

[The_Jerbel]

If the leak is HUGE the boost gauge will show it, if it's small, you won't see it unless you log or pressure test.