99 a4 1.8t boost problems
 

around 3k rpms when my boost starts to kick in the lights on the dash flash then the car basically shuts off then once it drops a few rpms it will kick back in and shift but everytime it makes boost it freaks out and flashes lights and kills the car. no check engine light on unless it flashes when it dies

The flashing check engine light is showing that you are misfiring.

The next step is to scan for codes. Do you have a vag com cable or know someone who does? If you do not you can buy one for $5 shipped on ebay, VCDS Lite (the diagnostic program) is free and will allow you to scan for codes.

You should have at least a P0300 (random multiple misfire) and P030X (X being a cylinder #).

Most misfires are caused by a bad ICM or coil, but we can't know until we talk to the car. ;)

i had this issue when i first installed my chipped ecu. i closed the gap on my plugs a little, and it all went away.

Try and replace the vacuum line from the DV, I had just done mine. If your car was fluttering after an ecu upgrade like mine was, I first thought its a BO but when I installed a boost gauge, the needle wasn't moving so I tracked the source and found that that vacuum line was completely gone. Ripped/Shredded. Got new one in, holding 15 psi, peaks at 17 and now producing a proper BO without any flutter. Good luck.

Any pictures of such line

No pictures needed, look at your Diverter Valve, its the thinnest hose connected to it, remove it and fit a new one.