1999 A4 - Call me crazy but I've tried everything

I bought a used 1999 A4 1.8T - Auto: the previous owner had upgrades like ECU - Turbo - INtake - intercooler etc but something screwed up and he converted everything to stock:
Now the problem is above 4-5k RPM it stalls...like missing etc I've checked everyhose for leaks but cant see anything obvious I changed
1) MAf
2) ICM
3) ECU
4)TB
( I have another 1999 A4 - so parts arent a problem)

there is sucking sound from the left side ( turbo / Intake) like its trying to suck extra air but im out of options;

and yea for codes only Missing Firing cylinder 1 and 3

Options remaing;
1) I also noticed it has green injectors vs black/blue on my other Audi could that be the reason?
2) Can a bad plug cause this? ( im changing them tommorow)
3) Fuel system?
3) Coils?
4) If Diverter Valve is shot could this be the prob?

what else ??

Change your plugs, gap them correctly. Clear the misfire codes. Then switch coilpacks from cyls 1 + 3 to 2 + 4, and see if you get a misfire code on cyls 2 + 4. If you do, those coilpacks need to be replaced. You can/maybe should order a whole set of 4 coilpacks to save yourself the trouble.
 
The sucking sound could be a vac leak... and if it is leaking long enough, you'll probably get a CEL for long term bank 1 too lean or too rich.

I had the same problem and changed all 4 ignition coils/coil packs. They are every easy to switch and i get them at the audi dealership for 32 each. (make sure you know your engine code)...mine's AWM

its .028 for the gap...Ill do coil change first

but the sucking sound is from or near the Airbox - where the intake tube goes in...

what about the DV

If your ecu is stock, gap to 0.032". Gap plugs to 0.028" if you have a flashed/chipped ecu and you boost around 16psi or more.

just thinking - Im hearing the sucking sound only when its missing....so this could be something like coils etc cause Im pretty sure there's no leaks... what really happens if the DV goes bad? (I have a spare from my other car)

ok ... im back.. changed plugs switched coils... same ****!!!!.... this is driving me insane!!... what now???

if DV is messed up would it do something like this? or Turbo screwed up?

??

Today I changed the Water Collant Sensor to...so Im really in a HOLE!! same fkn ****!

Find yourself a propane torch (don't light it ) and spray it around the engine while its running. If the idle shoots up there is a vaccum leak.
A cracked turbo manifold can also cause miss-fires.

A new Turbo was put in a month ago... so im pretty sure its not that...will give it a shot to

LATEST: The car started n I drove a couple of miles not to bad reved to 5-6k Rpms and then CEL started flashing I made it home and now it doesnt even start..... the CEL light flashes and cranks thats it?

I already changed the ICM from my other 1.8T still nothing also tried swapping ECU, Temp sensor still No life ...MORE Fkn Problems!!

you gotta pull the codes again. don't clear them w/o writing them down first, or it will be become even worse to diagnose the problem.

Ok ..im back with same old misfiring codes I checked and the plugs we're soaked hence no start...

I put in the old ones and now its starts fine but I have  code P1545 for the throttle which is trying to adjust itselft ( will do the 3mins on positions today - I also have a spare one which I might fit but that shouldnt effect the car going over 5-RPM does it??

otherthen that I sealed/checked every hose/pipe/ clamp! and secured...and by checked I mean replaced alot to!! I havent had the guts to go over 4-5RPM cause I feel it wont ( just scared) to be disappointed but have to tonight

and yes Im taking it to the MEch I cant deal with this crap anymore!!