Throttle inversely affecting Acceleration.

**BNZ TOY** · 03-28-2008 08:51 AM

Noticing this more and more as of late but here is a really good example from yesterday, what do you think is going on?

Accelerating full throttle up a hill (southbound on Boundary Road by the Costco). Both in 2nd and 3rd I notice that accleration is sluggish, not really surprised as i know my car is slow, BUT *just as i start lifting* my foot off the throttle, the car surges forward for a second. Put my foot back down and it's mediocre acceleration, the instance i start to lift up my foot, it's like the car lost 500 lbs and leaps forward for a secound.

What is goin on

I'm not imagining this, my friend in the car noticed it as well.

**Amze** · 03-28-2008 09:00 AM

My car feels faster at 3/4 acceleration than full accelerations sometimes...

Effing weird.

annoys me.

**sailor** · 03-28-2008 09:04 AM

Is it possible the knock sensor is kicking in at full throttle?

**NiveK1970** · 03-28-2008 09:19 AM

possible more fuel than the car can consume? or not getting enough air to burn all the extra fuel at full throttle?

**BNZ TOY** · 03-28-2008 09:27 AM

Sailor, is a vag-com the way to check that?

Nivek, I guess a 1+ would remedy this if it were the case.

**Tgr_Clw** · 03-28-2008 09:31 AM

Scan for codes. One of the coilpacks may be on its way out.

**BNZ TOY** · 03-28-2008 09:41 AM

Thank Tgr, I'll give it a shot.

Anyone have this experience though? Doesn't it sound weird/stupid for the car to accelerate better at 3/4 throttle than at 100% throttle???

**sailor** · 03-28-2008 10:00 AM

I don't know that much about how our Audi's work yet, but a lot of things can cause an engine to choke at full acceleration. Any mismatch in fuel/air/boost ratios. Even a colapsing fuel line or filter can cause these sort of issues, but I would expect something simpler. What happens when a DV fails, or like Tgr Clw suggested a coil pack. How about the MAF?

**mtbrider** · 03-28-2008 10:47 AM

That's DBW for you. I was speaking with a mechanic friend of mine and he said that the same thing happens on his B5 S4. Apparently there is even a mod for the S4's so that when you push the accelerator all the way down, you only go 3/4 down keeping it in the "sweet spot".

**BNZ TOY** · 03-28-2008 01:27 PM

From what people are saying this isn't really that uncommon. I guess I'll just wait and see..

It's not a big deal, i dont go WOT often anyhow - but when you need to slip into the center lane from the parking lane and sometimes the guy in the centerlane doesn't want to be passed haha.

**AWDTurboLuvr** · 03-28-2008 02:56 PM

Maybe your turbo intake pipe is collapsing?

**durfA4** · 03-28-2008 04:35 PM

What it is more than likely your fuel trims are off, Boost leak most likely, the ecu switches to open loop on WOT and uses the stored values, when you go off throttle your in closed loop and the ecu calculates your fuel and timing using the O2 sensor, so your ecu making is prime power. thats why all these tweaks with Chips, SAFCs, etc (not audis but the idea is the same) with fuel effect closed loop.