I'm the new owner of a 2002 GS 300. I've been going through it replenishing and renewing and I've just discovered what's involved in changing the spark plugs.

I thought my wife's PT Cruiser was bad. I looks like it will take an hour and a half just to get at the things, and another hour to put everything back together!

So I've given the matter some thought and I'd like your feedback on the following points:

1) In my experience plug wires last from 35-45K miles.

2) Given the amount of effort involved, the extra effort of changing the spark plugs is insignificant compared to the effort involved in getting at the spark plugs.

3) So if you're going to be changing the plug wires every 40K, what's the point in having 100K exotic metal spark plugs? I can't see taking the intake system apart and putting it all together again without changing the plugs while you're at it. So why not use cheaper 40K plugs and change them AND the wires every 40K?

Your thoughts and recommendations for suitable plugs would be appreciated. I do want a plug designed for the wasted spark ignition used on the GS 300, i.e. a plug with special treatment for both the electrode and ground. Thanks.

 

I am not sure where the 35K to 45K came from on the plug wire change but I am making my first wire change in a few days and my '00 G3 has 182k+ miles on it (previously changed the plugs). And that's preventative maintenance. They are not causing any problems. I just think it's about time. IMO your assumption about wire life is incorrect for these cars.

The effort to change the plugs is not nearly as easy as in the old days when you popped the plug wire off, slipped on a plug socket and took it out. On the other hand, It's not bad as what you may have heard or appears. You don't have to take the whole intake off, just the MAF and throttle body and associated hoses and tubes. It should take no more than hour and a half from start to finish.

You'll spend time cleaning out the plug valley as much as anything else. You didn't say how many miles were on the car. If it's over 100k, then you can expect the wire connectors to crumble when you try to take them off; that and the wiring harness cover will be brittle. You'll have to clean up those bits of plastic to keep them from falling into the cylinders when you remove the plugs. Also, if it's a high mileage car, the valve covers are probably be leaking too. Which means the plug valley will have oil as well as dirt and plastic bits.

I didn't realize I had so much broken plastic bits until I had pulled out a couple of plugs. By that time, bits of plastic and oil had fallen into a couple of the cylinders. I got a small shop vac from Wally World with a computer cleaning kit included - paid $30. It had a funnel-shaped attachment with a pencil-sized opening. I taped a drinking straw to it. The straw taped to the attachment was perfect for vacuuming the oil and debris from the top of piston head. Because the straw was flexible, it could get down into the hole to the base of the plug. Be smarter than me and use it before you remove the plugs!

Using anything other then twin ground platinum or iridium plugs is a mistake. I don't use anything other than Denso and NKG in my GS300. These cars are very finicky when it comes to spark plugs. Bottom line, change your plugs and wires using quality products and you won't have to worry about them again for a long, long time.

Hope this helps

 

These cars are not like your typical American cars. The plug change intervals are every 120k miles with the iridium plugs, and the timing belt is every 100k(I have seen some go 200k+ on orignal belt!). There is no specified plug wire change interval, you just change it when the car has a misfiring issue. I have seen some of these cars go 350k+ on the original wires!!! Also have seen a few of these cars go 200k+ on the original plugs! The crazy part is that the car didn't misfire at all or act out of the norm with the old plugs and wires. They were just changed out for preventative maintenance.

Don't use the platinum plugs, they are inferior to the iridium plugs because they don't last as long. The older cars specified platinum in the manual, but put iridium plugs when you do the change. It's the same engine, Toyota just changed the specified plugs to iridum on these cars at year 2000 or so.

 

Also make sure theyre twin electrode.

 

Funny...that's how I changed mine on the 400. Unscrew the pack, slip the socket in an wrench. Simple. Plugs took me 30 minutes on this car. Not complicated.

 

Just changed my plugs and wires on my 2002 GS300 last week. Car has 110k miles and has been very well maintained. I have picked up 1-2 mpg on the highway and much better response. I used the Denso IK16 Iridium plugs and the Denso wires. Why not use a good plug and doing it right the first time for a few more dollars.