have you checked for any leaks or hoses that came off at all or did you only check the gas cap?

 

the sewell part the I ordered came in, but that's not the culprit.
I was under the impression that it acts like a one-way valve but apparently it's not.
So now I would have to jack the car up and go underneath to check for loose hose and check the vacuum switching valve.

 

I am going through the same thing right now...Please let me know what you find out. This is getting annoying

 

basically I'm just following the sewell parts diagram to find out where the parts are located. there's like 2 vac switching valve inside the engine bay and 1 on top of the charoal canister.

 

CANISTER ASSY, CHARCOAL 7774030261 $280 shipped

 

^wheres this price at?

 

Sewell's has good prices on parts.
You can check there.

 

Well I have Inspected most of the vac lines and havent found any cracks. I replaced the VSV at the charcoal and my CEL is still coming on at 17.1miles after reset.

WTF!

 

I think there's like two more solenoid valves that you can check to make sure they're not getting stuck.

 

Yesterday I finally got around to removing the VSV from the charcoal canister. I hooked it up to a battery and it wasn't working. So I went online and checked out the napa autoparts website. They got it for $67 before taxes. I called the local store and they said they can get it the next day, which is today. So first thing in the morning I picked it up and installed it. I cleared the CEL by disconnecting the battery and now I will just have to rack the mileage to see if the CEL comes back on. I'm hoping it doesn't!

Here's the part number for the VSV CRB 228207. This is for a 98 GS400

 

How did you removethe VSV??

 

Without removing the axle, I removed the 4 nuts that's holding the charcoal canister. This makes it easier to access the VSV. Then I unscrewed the one tiny screw that's holding the VSV. Make sure that you remember where the hoses go. I took pictures of where the hoses go. The wiring harnesses are not interchangeable so you won't have to worry about hooking up the wrong one.

 

Could you post the pics you mentioned?

 

http://www.lexuspartsnow.com/parts/l...740-30261.html

 

Sorry bro but right now I'm not incllined to jack up the car and get underneath to take pics as it is cold outside. If you look at the charcoal canister you will know what I'm talking about. The VSV is a blue green colored cylinder with 3 small hoses attached to it.