Doneve79

Hey fam, it's been a while. Well, last week my 01 Gs300 threw multiple codes P0300, P0304, P0305, P0306, P0171, P0174 etc... so, today i removed the intake, coil packs & wires, then noticed all my plugs were soaked almost to the top. Funny things is...i dont see any oil leaks from the valve covers... so, were could it come from?

Thanks im advance for your suggestions & opinions.

zippymbr

The oil came from the valve cover gasket fail. The valve cover has seals around each spark plug hole. This is a common problem. The oil causes a misfire hence the codes you are getting. Buy a valve cover gasket kit, clean out the spark plug recess and coil boot and you should be good.

Doneve79

Im not too sure about the valve covers. I have no oil residue around the covers. Plus, the valve cover gasket set doesnt have rings for the plugs.
Here's the set:

zippymbr

yes that set does not have the spark plug seals. This valve cover is strange and in 3 pieces. Those seals are for the cams. Look at Rock auto parts

zippymbr

Look for the ones listed with spark plug tube seals

zippymbr

Most of the oil seeps out of the side gaskets down into The trough

Doneve79

Okay, I'll look for the 3piece set. However, the 2001 GS300 comes w 2 separate valve covers, and there's a channel in bettween where the coils & wires goes. There's no way to remove the channel in order to install the spark plug seal.
Here's a pic from the sticky DIY section showing the valver & the plug channel in between:

FrankT

No tube seals in a 2JZ motor.

Doneve79

thought so too

zippymbr

Oops my bad. I forgot which Lexus I was working on last. My wife has the GS