View Full Version : 1.8t Stutters under heavy load only

02-07-2014, 07:05 AM
I dont post here much as I search and normally find my answers for anything.

I was doing my turbo back exhaust yesterday because my flex pipe ripped and thats where my exhast ended at. So i removed the intake off the turbo to have more room, front 02 sensor and couldnt get the rear sensor off so i put it back together made sure everything was plugged in exc. It runs fine no stutters nothing at idle, you can rev it up to max rpm with clutch in no misfires nothing but when your driving and give it enough gas to go into boost or decent accel it bucks and stutters. I can go 80 on interstate and not a misfire at 3500 just smooth. Any ideas

02-07-2014, 07:26 AM
forgot to post No codes besides rear o2 not warmed up, rear 02 not plugged in lol. it was plugged in when this started. only thing i can think of is intake because i didnt do anything else.

And i will paypal someone 20 bucks who gives me the correct answer on here that fixes this problem. Ill try your idea if it works ill shoot the money over gift style.

02-07-2014, 07:45 AM
Info on the car? Year, upgrades.... And what codes is it bringing up if any?

02-07-2014, 07:46 AM
I had the same problem and what I did to remedy it was to change the spark plugs to NKG BKR7Es at 0.028 Gap (am chipped), got a new pre cat O2 sensor (had a code for it), cleaned the MAF with MAF cleaner. I also ensured that there were no hoses detached and that the vacuum lines were new (these came after I resolved the issue with the above 3 things).

02-07-2014, 08:13 AM
99 Turbo Quattro Manual AEB engine, Filter on intake this exhast and Forge diverter valve. No codes that it shows only codes for the rear sensor not working which it wont as its not plugged in, I thought it might have been the front 02 because When i removed it we wrapped it in paper towels so it wouldnt touch anything else. But it idles fine drives fine not under load. Like i said i revved it up alot and it just flew through the RPMs didnt miss or stutter at all. I am going to clean my MAF tonight to see if thats it.

02-07-2014, 08:52 AM
Plugs only have like 3k miles on them, but the car was fine before doing this install so i doubt they went bad that fast

02-07-2014, 09:00 AM
I'd definitely look into that o2 sensor and clean the MAF.

02-07-2014, 09:05 AM
Do you have a boost gauge? adn are you running stock ecu no chip? if so when you get on it what does your boost spike to?

02-07-2014, 09:27 AM
no boost gauge or boost controller, stock ecu no chip or tune

02-07-2014, 09:45 AM
im looking over things now, the harness that plugs into the maf and all those valves on passenger side. The last thing it plugs into is a 2 pin cylinder looking device. it was ziptied in and i know i had trouble undoing the plug on it so i may have shifted it, what is it? i just pulled it out and it has a spring and cup that goes into the vacuum lines.

02-07-2014, 09:48 AM
its below the pancake thing

02-07-2014, 09:56 AM
figured it out its an n75 valve, that could cause it right?

02-07-2014, 12:05 PM
Well I found the N75 had been ziptied to the boost connection, unzipped it and relaced it not at an angle that i moved it to went for a test drive and boosts hard to redline. I do appreciate all the help i guess i self diagnosed it.