replaced MAF after failed emissions and my car totally bogs when i tap gas, read on>
 

I failed emissions a couple weeks ago, the codes that were thrown were Mass Air Flow; running too rich. My car would also jump in idle back and forth from 600-1200 RPM's so i knew something was up. I replaced maf and spark plugs, got spark plugs from pure motorsports, they are copper tipped. The MAF is from a '99 Jetta, intake was modified, its got a 3 inch openening. Is there a reason why my idle would do that? is it because of intake? boost leak? vacuum leak? the car seems to idle pretty steady now so that is good. any input? thanks fella's

Well, its not the right MAF.

what engine?

the Prev Ownr totally re modified it. hes got a FMIC and it goes straight to a u pipe then a>
 

cone filter. what would it take to get back to stock intake? can i even do a stock intake with the FMIC that ive got on it? Its a Hartmann Motorsports Intercooler

sorry always forgetting to post engine, im newb. a4 1.8t manual atw motor

Oh yeah. A lot of big turbo guys use the stock intake because its got such good flow
 

I'd say find someone who is parting out their car and see if you can nab the airbox and related parts.

are you tuned to use that maf?
 

what type of turbo do you have?

"ko4 sport hybrid" according to PO by tuned do you mean chipped for the maf?

what type of programming though?

According to etka a 99 jetta's maf sensor is p/n 06A906461L
 

and a 99 a4 1.8t's p/n is 037906461CX ... so I believe you have the wrong maf in there.