B5 audi a4 sputtering between 3-4 rpm
 

I have a 99 b5 audi a4 1.8 with a gt2871r turbo with 440cc injectors and a mika tuned ecu. I have replumbed the whole car and cant figure out why i cant boost over 18 lbs. And the turbo starts sputtering between 3-4 rpm. Also no matter what i do the stock boost pressure regulator doesnt work so i ended up hooking up a greddy electronic boost controller and thats what allowed me to boost to 18 lbs. But without the aftermarket boost controller i was not boosting over 10 lbs. I need help. I changed the spark plugs repiped the whole turbo plumbing changed the engine harness tried to clean the intake manifold and so on and so fourth. Then one of my buddies has a similar setup so we took out his ecu and plugged mine in and his car actually started to run stronger with the mika tuned ecu. We also then plugged his ecu and the car would start but it would shut off. Felt like it wasnt getting enough air or fuel. Can someone please please help me with this?

same problem man. with my MAF plugged in i couldnt get over 3-4000 rpms.. and was very sluggish. replaced numerous of parts..and then just ran my car without the MAF for a couple months.. but my turbo just went out yesterday... so now my car is parked and about to get ripped apart. once i get a new turbo on i will let you know how it works.. ive done all the usual stuff to try and fix it..new MAFs(3), n75, PCV, coils, sparks, tried different gaps on the spark plugs, new MAP sensor...stock ecu..fuel filter..