I own a 2000 audi a4 1.8t awd ATW motor.

4 weeks ago i installed new plugs, K&N filter, and Forged DV/BOV. and now i think i have a vacuum leak. My car has a rough idle for the first few minutes. It lacks of power and studders on fast acceleration. And also studders when on and off the gas (between gears or just on and off). I installed the factor DV to see if it helped... none. Also after the BOV blows off i can hear it for a few seconds suck back in air (very loud and obvious). It also doesnt close fast after blowing off. This is my assumption of the vacuum leak.

Any help would be a great.
, Thanks Chad

Plugs are gapped correctly and had no problems untill after four weeks... not directly after replacement of anything

 

clean your maf sensor i put a k and n filter on my car and the oil on the k and n fould the maf sensor causing the car to go into limp mode so i really am against k and n on our cars so get some maf sensor cleaner and see what happens

 

hmm ill check it out tonight... any other thoughts? it's bugging the **** out of me... she runs so poopy... it might as well have 80 hp lol

 

do you have a boost guage are you tuned?

 

dont get my boost gauge till next week..and wont hook it up till next month... =/ got new valves, all new gaskets, headers, and turbo coming... and 10 ft of vacuum line... so i plan on replacing a lot. so hope i find whats wrong soon.. might even get a vag com... is a cheap $50 ebay one suffice? says reads and clears codes. the codes from auto zone said misfiring because of lean fuel pretty much. and said probable cause of vacuum leak or MAF or O2 sensor... it honestly said like a hundred different things, so they dont help much

 

soo i went to check the MAFS and i found something... on top of the air box. there is a little vacuum check valve or something... its fairly small. it has a special clamp on the passenger side and a normal screw clamp on the drivers side... it is white on the driver side... what is this specifically called because i need to find a new one, i found a huge piece of it missing... must be my vac leak

 

Install that boost gauge asap bro. Honestly, these cars can be real bitches and the longer you let a problem go, the more you will end up having to replace...just my $.02