# Power loss and hesitation when warm - Losing My Mind !!!



## underdog is here (Jul 20, 2009)

I've been fighting this for a while now, and thought maybe someone would have an idea that I have overlooked.
Specifics: 2001 Audi A4 (b5) - 2.8L (ATQ) - Manual Trans. - 75,000 mi. 
Symptoms:
- Runs great when cold lots of power. Good Idle. Occasional slight hesitation, but no big deal.
- After warm up, at normal operation temperature, moderate power loss across the whole RPM band More power loss above 3000 rpm(can't tell if the manifold change over is working or not) Not as much torque as before.
- Feels sluggish and powerless even at WOT. Actually, from WOT, if I let off the throttle almost all the way, it feels like it gets a power increase!!
Recent Parts: 
- Plugs
- Wires (Dealer Parts)
- ECT sensor [engine coolant temp sensor] (Dealer Parts)
- Valve Cover Gaskets
- Crankcase Breather Hoses including suction pump (all replaced)
- Some vacuum lines replaced
Other Info:
I don't have a VAG-COM or access to one, but no CEL's. 
Tested the coils per Bentley manual, and checks out OK.
This car actually ran BETTER before I changed the valve cover gaskets, but it was leaking oil like a sieve. When I was doing the gaskets, I broke the breather tube, so I replaced the whole assembly including the suction pump thing (plastic Y) While I was in there I replaced some old vacuum lines. It seems to have lost power since then. I have checked everything a number of times, but I can't see any problems. 

Any Ideas?????


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## -(Dubslinger)- (May 29, 2008)

*Re: Power loss and hesitation when warm - Losing My Mind !!! (underdog is here)*

ive been having the same problems with my vr! wtf


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## MEDEL514 (Jan 12, 2002)

*Re: Power loss and hesitation when warm - Losing My Mind !!! (underdog is here)*

I think I'm having this problem too. I took the car on its first road trip this weekend since rebuilding the motor, and after a couple hours of driving, I pulled over for gas, and getting back on the road I noticed hesitation while taking off at lower RPM's. At cruising speed she was fine, just accelerating in lower gears I felt a hesitation, almost like a misfire, of a bad plug. I need to look into it, but I don't know where to start...


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## -(Dubslinger)- (May 29, 2008)

*Re: Power loss and hesitation when warm - Losing My Mind !!! (MEDEL514)*

i just replaced my cat... seemed to get a lil power back.... going to keep troubleshooting


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## ParkPass (Nov 26, 2009)

anymore ideas?
I bought a 4 motion (2000) and notice the same slight hesitation in lower gears accel... wasn't sure if it was a normal for the all wheel drive! don't feel much in triptronic mode!


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## walkingfool (Mar 24, 2008)

*Re: Power loss and hesitation when warm - Losing My Mind !!! (underdog is here)*

Made any progress?
I have VCDS and would be glad to do a scan for you, if you can get out to Lansdale (which is the first exit off the northeast extension of the turnpike)


_Modified by walkingfool at 3:03 PM 12-3-2009_


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## HARERZR (Sep 5, 2009)

*Re: Power loss and hesitation when warm - Losing My Mind !!! (underdog is here)*

Anyone else's check engine light on? I've been having this problem since I did the timing belt. Cleared the check engine code and problem was gone for the first 2 or 3 starts from a stop then comes back accompanied by the check engine light. Code is for a vacuum leak I can't find.


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## vital101 (Dec 8, 2009)

I once owned a Golf 2.0 (1996), and I experienced the same problem. As it turns out, all of the catalyst from my catalytic converter had come loose and shot back into the resonators and muffler behind it. This caused me to loose all sorts of power when the car was warm (the catalyst would expand), but when it was cold it ran great. Might be work knocking on your resonator(s) further back to see what kind of response you get. In my case when this happened, I got a dull thud when I tapped it with a hammer.


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## Peter Badore (Jun 17, 2002)

*Re: Power loss and hesitation when warm - Losing My Mind !!! (underdog is here)*

You need to check your MAF sensor using a VAG-COM if possible.


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## underdog is here (Jul 20, 2009)

*Re: Power loss and hesitation when warm - Losing My Mind !!! (underdog is here)*

Thanks for the replies guys. 
Walkingfool - Big thanks to you! I might take you up on your offer after the holidays. I'm pretty close to you, I work in Eagleville. 
I've been busy for the past couple weeks, and have not had much chance to work on this, BUT...
I tried running only premium gas for the last couple of tanks and it helps a lot. The hesitation and power loss are still there sometimes, but it's better. So, that makes me wonder abut timing. Also, it's been a lot colder outside recently which helps.
I never ran economy gas, but usually like 91 octane stuff. So what does everybody else use? I know these motors have the knock sensors that retard the timing when ignition knock is detected, but I did not think that it would be enough to have substantial power loss. Now I'm not so sure. Could be a contributing factor.
I guess it would make sense though, that it would run great until it warmed up and then that's when it would have ignition knock...... if it didn't have knock sensors that sent a signal to retard the timing! Hmmmm.
Anybody have thoughts on this?


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## Peter Badore (Jun 17, 2002)

*Re: Power loss and hesitation when warm - Losing My Mind !!! (underdog is here)*

Have you tried driving the car with the MAF sensor disconnected? I have had several 2.8l V6 30V engines that suffered from bad MAF sensors recently without DTCs!


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## -(Dubslinger)- (May 29, 2008)

*Re: Power loss and hesitation when warm - Losing My Mind !!! (Peter Badore)*

ok so question. will running a obd1 maf cause this to happen?


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## underdog is here (Jul 20, 2009)

*Re: Power loss and hesitation when warm - Losing My Mind !!! (Peter Badore)*

Thanks for the tip Peter - 
I have not tried driving with the MAF sensor disconnected, but I will give it a shot today if I have time.


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## pennell33 (Feb 17, 2008)

Anyone figure out what was causing this?


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