i have a 1998 audi A4 1.8L turbo. for the last month i have had a serious loss of power, CEL has been on. at first the VAG - COM said it was the turbo boost valve, so i replaced that and still nothing. then it said i was the Mass Air Flow Censor, so i replaced that and still nothing. the check engine light is still on and it still says MAF. but a couple days ago it went of for a couple hours and i could hear the turbo again and had a bit more power, but not as much as i used to. any idea's?

 

whats the mileage on the car ? ever done the coils ?
when u go into boost the car doesnt move and the engine light comes on right?
coils...

 

mileage is 187000km and no i havent ever replaced the coils. i still get some boost sometimes and the car still runs fine, just no power, especially in the higher gears and only somtimes i can hear the turbo and the blow off. Also the engine light is almost always on.

 

my car when into limp mode last week(check engine light was on). It was just chugging along, shaking, hard to change gears, no turbo boost at all.

Replaced 1 blown coil pack and its back to life!

 

if it's a coil you should have a cylinder misfire code in the ecu.
A4 1.8T's like to blow a little hose close to the manifold. i bet it's that.

 

i checked the vacuum line, thats good. is there anyway of checking the coils without replacing them?

 

you said you have a vag-com. post your fault codes please.

 

no, i dont have a VAG - COM, i had it in at a volkswagon dealership and thats what theirs said. here's excatly what their last report said after replacing the turbo boost valve and MAF (Check engine is still on saying MAF). "checked and found turbo not boosting at all. removed pipe to throttle body and found very little boost pressure. checked for pressure just after turbo outlet and found same thing. performed output test on turbo boost valve, working fine. wastegate not moving. put pressure on wastegate control pot and it moved, but did not increas boost any. block hose for turbo bypass valve, did not change anything. removed intake hose to inspect turbo impellor, and turns freely. may have blckage on exaust side of turbo or damaged exhaust compressor wheel causing no boost. suspect faulty turbo charger, will need to remove turbo to confirm."

 

Did you solve this issue?

 

no, i sold the car haha