I have a 2001 jdm sti....its basically all stock. I was using it for almost 6months now with out any problems...until a month a go things start to deteriorate.
First thing i noticed its that...the usually pull i get when i first drove the car isnt the same as it is a few weeks ago. I checked the boost it was still on 1.5bar.
Second i noticed is...i get knock on upper rpms and no pull at all.
Worst of all when i was driving it this morning...the boost only reaches .5bar.
I'm particular with maintenance...and i follow the usual guidelines....I tried logging it with a ecuexplorer and one thing i noticed that is quite abnormal is the fuel pump duty at idle is 33% and mid rpms at 66.5% and at 6000rpm up its pegged at 100%. Could this be the problem?
I have done the ff..
1. checked for boost leaks or lose hoses....no leaks.
2. changed the plugs to a new one.
3. changed the fuel filter, airfilter, and oil
but still its the same...
ANY SUGGESTIONS ON WHAT ELSE I WOULD CHECK OR DO?
Sorry for a long post....Thanks in advance