bell206doc

Alright guys and gals, I have been on this site for about 2 years now reading and learning,
But i desperatly need experienced technical help...Some days it runs great other days are terrible. I have a 03 DSG GT, 68000 miles, and for 1 1/2 years now now i have been fighting a BOG on take off, light stumble/ miss @1200-2000 RPM or 45 to 55 mph, when I accel medium to heavy (like passing on the highway) my car smells like rotten eggs, and an idle that feels like i have aftermarket cam. also when i shut car off, it sounds like it is literally Farting (no other way to describe it)... and no CEL EVER! NO STORED DTCs!!! I have had it in the shop 3 times and no one can understand whats wrong with it, all mechanics agree somethings wrong but, cant find the problem. Ive had it to 2 different private shops and a dealer.

This is what has been done, hear goes.

tune up
New plugs, COP boots,
Injectors pulled and cleaned
IAC replaced
DPFE ck/replaced
EGR ck
Modus scan too 2 times Found #5 #7 intermittent miss, moved COP, no chg
power balance 2 times
compression ck ok
fuel system ck ok
electrical system ck ok
looked top to bottom 2 times
replaced maf no change
Vacuum Leak ck ok
4r70w tranny Ck ok

Guys and Girls, PLEASE HELP!!

sweger

what kind of mileage are you getting? fuel filter is good?

bell206doc

Yes i have new filter, and I get roughly 190 miles to a tank

WhiteFoxGT

Stock h-pipe?

Could of had a misfire that clogged up one of your cats.

Try borrowing someone else's h-pipe and see if the problem persists.

mrtstang

Wow... only 190 miles a tank?

I get around 290 a tank.

sweger

good thought whitefox.

190 is rather low...i normally get at least 300 or so

bell206doc

Hello,
Yes, the car is all stock except for a K&N Cai that was on the car when i purchased
it, unfortunatly i dont have access to part swapping, but my exhaust was also checked
for restrictions, no faults there, I have the mod bug bad, but cant see doing it until it runs like it should lol

cliffyk

"190 miles to a tank" doesn't mean anything, because "a tank" is not a standard unit of measure--how many gallons do you typically pump when filling up?

OTH, if you are filling up at 1/8th full or so (typically 12.5 gallons or so) then you gas mileage sucks, at 15 mpg or so. Unless you do all city driving at 45 mph or less.

I do not see O2 sensors on you list of changed parts--as they age they might stil be switching and making the PCM happy, however their output voltage drops. This tells the PCM that the mixture is lean, the PCM compensates by enrichening the mix--often this will not trigger a DTC it just makes the engine run pig rich, bog, and stink...

A check with a wideband sensor would confirm it's running rich, or just toss in a couple of new front sensors (at 68k it's due, particularly if you do only short in-town trips) --they're $50 to $60 each at your FLAPS.

bell206doc

Yes, Sorry, when i fill up it usually takes 12 gallons, and honestly it doesnt matter if its city or highway, it uses the same. and I understand what cliffyk is saying about O2 sensors, both times it was put on the modus, the mechanics said they
were "within parameters" I may need to clarify BOG, When i pull from a stop, If i take off normal, it will feel like a dog, no power for approximately 1-2 sec, then it takes off like a mustang should.

sweger

sounds like mine does when the traction control kicks in...it bogs down until the wheels arent spinning and then takes off like normal. maybe its a timing issue for you? i dont know much about this stuff, just spit-balling...