OK, I have a 1999 1.8 that I keep having an issue with. Under hard acceleration I get a surge I can feel in the pedal. It feels like it is backing off but is very unconsistent. If I accelerate gradually I don't notice it but any more than half throttle and you can feel it sort of backing off. Any ideas as to what may be causing this.

 

Are you chipped? Do you have a boost guage? Any CEL?

You could have a boost leak somewhere in your vaccumm lines.

 

A worn out DV will also cause this.

 

I thought the DV might be the problem. It acts like it is releasing the boost under hard acceleration where when under gradual acceleration it can maintain.

 

Could deffinately be the DV... Until recently i was under the assumption that only 2000 and up a4's were dbw.. But i read a thread a couple days ago that some 99's might have dbw also.. If you are dbw, a sensor in the gas pedal mechanism could be bad.
But honestly, it could also be normal because the stock turbo loses its momentum past 5k rpm's and isnt efficient after that... What do you expect from a turbo the size of your fist?? Check for leaks. The least expensive cost approach to diagnosing this is-

1: Visualy check for leaks
2: Get ecu scanned at autozone for free for stored fault codes
3: Replace DV
4: Make a boost leak tester (instructions from here, or audizine or audiworld.com)
5: Have a pro check it out that isnt the dealer, unless you have a bankruptcy lawyer on speed dial or some KY on hand for an extreme **** intursion.

 

I thought the DV might be the problem. It acts like it is releasing the boost under hard acceleration where when under gradual acceleration it can maintain.

 

I have a buddy I just talked to who has the VAG software on his laptop. We are going to throw it on there next week sometime and see what it comes up with. Thanks for the info.

 

strange thing that as mine does that when the aircon is on like its not enough amperage to the battery to compensate for the engine load so im looking to change the alternator and battery through the dealers of course because I think they got their math wrong on the output

 

yea mine does that too i need to figure it out