Car keeps going into safe mode

[KUTCH]

Basically I have a 2001 audi a4 1.8t. I have upgraded to the ko4 turbo, giac software, bosch injectors (380cc), tt maf, and fmic. The problem I am having is my car keeps going into safe mode and the codes I get are mixture adaption:system too rich and catalyst system:efficency below threshold which has always come up because I have a test pipe. I have had this upgrade for two years with no problem. The car would boost between 15 and 18psi. Now all of the sudden the car will only boost at 6psi. I take it into the shop and they reset the engine code and it will run fine boosting at 15-18psi for about 25 miles, then the car will go into like a safe mode and boost at 6psi again, and then the check engine light comes on shortly afterwards. Have you ever seen this problem before The shop I take it to can t figure out what is wrong either. I did notice that when boosting after I reset the code it spikes at about 4500 rpms and then the boost slowly drops all the way to about 12 psi from 15-18 psi. Could that be a boost leak or is that normal I think it has always done that and can that cause the car to go into this safe mode. Please help I can t figure it out and niether can anyone else. Spending entirely to much money to figure out what is wrong

[dwi_gti]

had similar problem on my gti, going into limp/safr mod. turn out to be a bad throtle.

[mike-2ptzero]

I guess you dont have a vagcom? Might want to find someone with one or buy one so you can check block 032 to see what the fuel trim readings look like, they can give you an idea of what is wrong with the car.

[KUTCH]

How much did you end up spending on the throttle and what was your car doing?