- Lexus IS GS: How to Replace Spark Plugs
Step by step instructions for do-it-yourself repairs
Browse all: Lexus IS Engine and Powertrain Guides
Spark Plug Change for GS300
Last edited by byoung1; Mar 27, 2011 at 03:56 PM.
Last edited by RoboRam12; Jun 6, 2011 at 07:37 AM.
so far i have it has
from front to back
Plug Coil Pack Plug Coil Pack Plug Coil pack
here are some pics.
After tearing down everything to get to the spark plugs I noticed oil that leaked from the valve cover gasket. So went ahead and changed the gasket as well. About 29.99 from Autozone.
The car is a 2000 GS 300 with 95k
I replace the plugs with NGK Irridium (they work great)
Problems I encountered
1. Clips on spark plug wire break very easily (as mentioned before, but can still be placed back on without the clip part that breaks)
2. Forgot where to number all plug wires before removing from plugs
3. Alot of dirt and pieces of the plug wire in the spark plug cylinders
4. In my case oil was leaking at the back of the valve cover gasket so I had to replace gaskets
5. Needed help on location of critical locations where the gasket sealant should go.
6. You don't have to remove the whole intake manifold just half of it and lift it high enough for the valve covers to clear. (4 bolts on top 2 nuts under neath. I had to use and open ended wrench for the nut closer to the firewall)
7. When reinstalling I forgot to place the bottom (coolant?) hose to the throttle body. Make sure to attach the rear bottom coolant hose before bolting up.
8 Rear bolt (on valve cover and plug wire) was not as easy to tighten but still very doable with angle socket
PM me if you need any help
Here are some random pictures I took along the way (not in order)







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i was getting pissed off with ever thing that i need to take off and then the coil pack did not want to come off.
then i missed the firing order.
found some oil in the bay but i was not worried about it so much.
when doing this, i would recommend take your time. get the spark plugs and wires....
I've stuck with the OEMs or Iridiums without any issues. It's just kind of funny when you have guys looking for insane horsepower increases from a spark plug!
Save your money for other mods or fuel.









