Mechanics

SUBARU LEGACY KNOCK SENSOR PROBLEM

1996 Subaru Legacy • 114 miles

I have a 1996 Subaru Legacy GT wagon 2.0 twin turbo Import. My problem is after driving for a few miles/about 10 mins, I get a rattling noise from rear, sounds like something loose in fuel tank. Then fault code 22 (knock sensor) light comes on as car looses power/misfires/hesitates but never cuts out and idles/starts perfect every time. Sometimes light goes out and suddenly back to full power for a few mins until it happens again. Also when cold for first mile car is slightly hesitant but no noise or fault light.
Are all these problems related to one thing? Would faulty fuel pump cause rattle and loss of fuel pressure/lack of power. If so, would ECU read this as a knock sensor fault? Or is rattle totally not linked to problem and I need a new knock sensor?
Avatar
Kevbuddy49
November 27, 2012.



A bad knock sensor can cause pinging from the engine. Replace the knock sensor to see if that fixes the problem.

Thanks for your reply, but to be honest I have never noticed engine knock under load or at high revs, just the symptoms I mentioned.
Would low grade fuel (95 RON) have this much effect on a Legacy? The rattling from the fuel tank area is puzzling as it appears around the same time as the loss in power and fault light coming on. Thanks.

Tiny
Kevbuddy49
Nov 28, 2012.
Sorry for previous post. I meant to say I never noticed 'pinging' from engine either. Also as loss in power is happening, any attempt in acceleration is slow and just seems to make more noise from exhaust rather than more power. Thanks again.

Tiny
Kevbuddy49
Nov 28, 2012.