Did you order these yet? I bought some ngk Iridium and used them for only about 15000 miles then switched over to denso when i had my car dyno. If you want those plugs i can try and look for them as they are in my storage right now.

That's if the gs400 and gs430 uses the same plugs

 

Has anyone used these plugs yet?

 

I just changed my plugs out. 2000 GS400 w/ 104K. Used the OEM Denso's (SK20R11) which I bought from Amazon.com for $7.49 each (no tax)! Ordered one afternoon at 1:30pm and received them the next day at 3:00pm.... shipping was FREE! $59.92 for all 8! The owners manual that came with the car shows the gap to be .043. This is what each plugs was already pre-gapped to......... The ruber boots of the coil packs can be a real PIA! Four of mine had pulled off of the coil pack and were stuck in the hole. Took a whole lot of minipulating to get the suckers out! Good Luck!!!

 

How does the car feel with the new plugs..

 

I haven't driven her yet. Still up on jackstands as I am also doing: lower ball joints, tie rod ends and complete front brake setup. Might be another week yet before I am finished. I can say that the original Denso plugs I pulled out with 104K on them still looked relatively new and the gap was still at .043 on each one! That being said, I doubt I will notice much of a difference. And, I also cleaned out the throttle body and added a drop in K&N filter. The combination of all of the maintenance performed just may make me think it is running stronger and faster though!

 

So I thought I would update you guys. I did a plug change on a 2000 GS400 with 100K. The MAF, Throtle Body was never cleaned/serviced and this was the first plug change ever for the car.

It been about two weeks since I did the plug change, Throtle Body and MAF cleaning.

I have done about two tanks of gas and the performance is fantastic.

I was averaging about ~17 MPG mixed Highway / City driving before the service.

The last two tanks were more like ~20-21 MPG.

Almost 400 miles on one tank of gas to Tahoe and back. 400 / 17 = ( 23MPG) on 275x35x18" no less.

The car is very smooth, I'm a rather heavy footed driver and since the plug change the car feels like it woke up. This is without reseting the ECU.
I know because all my radio preset are still there after the plug change.

So, bottom line huge diffrence glad I didn't wait till 120,000 to change them even though thats what the owner manual states for 2000 GS400.

I would say I will do the next change at around 70k, so see you at 170K.