I was wondering if you could help. I have GC8 Impreza turbo -1999. It suffers badly from a sluggish power drop at below boost levels, in boost its no problem! It then accelerrates in a stop-start fashion, almost as though the handbrake is being pulsed on & off like a wave! I've so far replaced airflow, plugs, plug leads, boost solenoid, all boost pipes renewed. What else do you think could be causing this problem? i had a faulty lambda sensor thats wasnt working ive replaced it and this is whats happening now thought it was a faulty lambda at first so got a genuine one just 2 make sure

 

maybe a collapsed cat m8?
gav t

 

its decatted unless the up pipe cats gone ill have 2 check that cheers

 

Stop spending and get it into a specialist mate. You could save more money in the long run. Good Luck

 

uppipe doesnt have a decat in that model mate.