VY SV8 - Check Engine light and 40lts per 100km average,

[D-mac]

I drive a 04 vy sv8 man, done 190xxxkm just had tri y headers n high flow cats installed bit over a week ago. car has been running fine till today. Check engine pops up and car is running at 40lts per 100km average, us eto be 11lts, car has lost power too. could this be Oxy sensors? Gonna book it into Mechanic but want to suss it out my self if poss, save some coin. Any help would be great.

[Paulid92]

Sounds pretty bad! Does it run and sound fine even though it has less power? A mates car went into limp mode a few months ago, wouldnt do even 50kmh. Take it to a mechanic asap, or go on ebay and look up ELM327. I bought one a week ago and it works, should be able to get some engine codes

[Davidcoolaye]

Sounds like the Oxygen sensors have had it mate, doesn't know how much Oxygen is hasn't burnt so its telling the computer to dump more fuel in, running rich.

[D-mac]

Thanks for ur input boys, I managed to nurse the car to the mechanic n get it hooked up to the Scan tool and what come up was "Knock sensor fault" Mech thinks maybe the wires had been damaged during the installationof the headers. Gonna save my self some cash and climp under the car and check it out my self. Apparently its on the right hand side of engine near the engine mount. Ive Reset my trip meter an car is now recording 13lts per 100, use to run at 11, but anyways Il check out prob ASAP n keep you lads posted

[Surfwagon]

LS1 knock sensors are in the valley plate under the intake manifold.
As said above O2 sensor failure after fitment of extractors is quite common.