I think this is my first post as i only search if i need something but im kinda stumped here. Heres the story from the start...
bought 98 a4 for dirt cheap, ran good on test drive but was told that the boost wasnt very noticeable on the stock turbo setup so i had no worriess. i took the car to the DUBWERX here in cinci, they are the top performance vw/audi shop around and have done some work on my 318is and my friends m3. Had them do a run through of the car for issues. They found the wastegate was loose causing irregular boost, ac clutch was bad and there were some old misfire codes from a bad plug which i changed. I had an audi tt diverter valve installed since they took the turbo off anyway, dont ask why the tt valve, i trust my mechanic as he is also a friend and knows his ****, i dont think im shooting for 300 hp or anything (yet heh). They tightened the wastegate back up, apparently people just replace the turbo but he said they go this route with no issues. I also had the plumbing for a mbc ran. They pull my ecu to send it to apr and lent me an ecu that was already chipped, the car was pinging real bad under load so i had them put my stock ecu back in even though they think the loaner might have issues. I ran out of money to fix any other issues so i wanted to play it safe. With my stock ecu they managed to get 15lbs of boost from tightening the wastegate down a hair more, the car felt awesome but 2 days later it went into limp mode, it had codes for lean and rich, i dont have the codes handy unfortunately. they cleared them and it ran great again for a few days, then limp mode/ce light. They ran a smoke test and found the intake boot had several stress cracks and figured that it would make it run lean at high rpms and rich at lower so they replace the boot. the car ran good then limp again, now some new codes.... misfire #2 and misfire random. I remember there being a post about misfire #2 leading to the maf somehow but my mechanic thinks that being as my car is drive by cable the maf's are pretty reliable. The shop had an idea that the 15lbs was telling the ecu to go into limp because its not supposed to go over 9 or so. Now They removed the factory boost controller as a test so im at 6lbs always. A few days later ce light again, havent checked the codes yet but i cant tell if its in limp since to car is so sluggish under 6 lbs anyway. Anyone seen this senario, i really think its the maf, i cleaned it though. Audi wants 600 for the one for my car and ive seen them for 200 used, any other ones fit that i can try or how can i test it without vag, i have a multimeter, can i just measure resistance. I dont know if it matters but i have a hole in my flex pipe too, im gonna have that replaced asap since its annoying. I just thought id mention it since there is a second o2 sensor. Ill try to get the codes for you guys. Thanks and sorry for such a long post

 

you shouldn't be increasing boost with a MBC. let the chip do all the work. get a VAG and get some codes. also with the VAG, log block 003 on a 3000-6000rpm pull in 3rd gear to see the air flow readings. that'll tell you if the MAF is bad. MAF failure is not uncommon, and it should not be $600 nor $200 I'm not sure what you're looking at. They should be around $150 or even cheaper (depends on your engine code).

your goal should be to get the car running well while it's 100% stock. if it can't run well stock, there is no way it's going to run well with the extra stress of tuning.

 

If you are running the stock ECU and are running 15 psi, you are going to run lean and go into limp mode for overboosting. The ECU is asking for 7psi, giving fuel for 7 psi, and getting 15. If this was done by changing the wastegate then the ECU is seeing overboost compared to what it is asking for. Put the wastegate back the way it was.

If you have the APR programming in and you are getting random misfires, check the mass flow sensor. Also check the ignition control module and coil packs. Misfire on cyl 2 is often a ignition control module problem due to factory soldering issues on the ICM.

MAF is 80 dollars at ECS tuning.

 

Where's the best place to get ICM?

 

I just wanna thank you guys for the info. It turns out that it was the maf, they had a used one there for me to try for a week and it ran great, i still had my n75 unplugged for troubleshooting purposes. Once we plugged it back in still no codes so it wasnt running lean under max boost. just had a new flex pipe welded in and now it feels like a brand new car. It just hit 100000 on friday. My mechanic had a chipped ecu that he let me put in to put around in for a bit to see what it felt like and needless to say i wasnt putting. It felt awesome, im so excited to get chipped, it was a apr 91 ecu from a passat. They are gonna loan it to me when i send mine off. He also gave me a lifetime warranty on the maf since he has never seen one go bad for my model fuel injection. I drove one of the mechanics 99 gti 1.8t and i swear it was the fastest car i have driven, faster than my dudes m3, all he had done to it was a fmic and full exhaust and a chip, he runs 20-26 lbs of boost on stock internals and stock turbo and has been doing so for 50k miles, he said hes at roughly 275hp. I cant wait for the mods.
On a side note i downloaded vag-check for my pda and i need a cable, i have the usb to serial adapter but need the obdII cable, wheres the cheapest place, i have been searching but not sure what to look for i get mixed results. Eventually i will have vag com in my car on a mac mini running parallels.