Well, I decided to change the plugs in my GS guys.
I first went with a set of new Bosch +4's. Well-I should of known better. I put them in because I had them laying over from a previous car..Took them out very quick. A GTech run gave me a 14.5 average. Worse than before. Bosch never did run well in Toyota motors. Even the Bosch rep. told me this at our vendor sales conference last year.
I then went with the Denso Iridiums sold on Ebay. Best price I could find anywhere.
I removed the old OEM NGK IR plugs and found that when they were replaced last, the dealer gaped them wrong. They gaped them at .039 instead of the .044.
Im sure that it is a combination of things such as incorrect gap and some mileage on the plugs, but a profound increase in throttle response and power is very evident everywhere . I powered up the GTech and where I would normally average a 14.4 on this back road , I now average 14.2. Same temperature. Tank full. Same tires. 3 run average. Im impressed.
Just an FYI to you guy.
Total time for plug change-45 minutes.

 

if it's not a problem, could someone tell me hows the best way to get to the Spark plugs, I have a GS430, im not sure how different it is compared to a GS400.. hey Pearl, im curious, do u think that the factory would have gapped them wrong as well? because im trying to figure out if my car is putting down as much power as it should be, I've noticed a gas smell in my oil and I was wondering if the spark plugs aren't firing enough to burn off the gas completely, thanks in advanced for any replies

ShOwGS

 

Pearlpower,

how much did the densos cost you? thank you...

 

GS4will,
I paid about 96.00 total including shipping from NY. I got them from Ebay user: DOHCCivicNA1250@aol.com

ShowGS,

Plug change is the same for both 400 & 430.
1) Remove the engine cover
2) Remove the air filter assembly
3) Disconnect 8 electrical leads to coil packs
4) Remove 8 10mm bolts from coil packs
5) Remove coil packs
6) Gap and replace replace plugs. Put a tad of oil on threads of new plugs. Not much. Just the first 2 threads. Too much and the plug will not ground. Too little and you risk cross threading or damaging the aluminum head.
7) Put it all together

 

you don't have to adjust the gap for NGK IR when you get them, but i would double check them anyway.
OEM plug should be good for 100k mile

maybe you just need to re-gap and clean the OEM ones. That should be enough. you describled that the gap was .039 ==> what is why you don't make power...:eek:

 

OEM lugs claim a 100k life in idea situations, however many of us do not drive in "ideally" conditions. I would never go over 50k.

GAP should always be checked on every plug. I was told that the GAP on the Deno did not have to be checked either. I heard that one before. They were at .038-.039 from the box.
Smaller gap equates to a smaller spark in the chamber which could lead to imcomplete or not ideal fuel ignition.

The plugs that come out of the car were not bad enough to make that much of a difference and as I stated the new Bosch +4's performed worse than the used NGK's that came out of the car.

 

Isn't OEM spark plug Denso Iridium?

 

RA,
I thought they were Denso Iridium plugs as well.

Ragarding changing the plugs, I think Percy changed his plugs to a brand called Torquemaster, if I am spelling it right, and he said he felt a noticeable difference compared to the stocks. I am happy with the stock plugs, but I am starting to think maybe I should change the plugs. Quit confusing me guys

 

I know a place where they sell Denso IK20/ IK16 for $55 shipped. They are totally legit and locate in Los Angeles.

 

RacingAristo where can you get the denso iridiums for 55 bucks shipped?

 

RA,

I thought the same thing. Maybe the dealer got in a special deal of NGK's. When I had my SC4 plugs changed the same dealer installed Denso's. Go figure.
Let us know where you can get these plugs for 55.00. That is a great deal. I would like to have another set.

 

I swear by my torquemasters.

 

http://www.groupbuycenter.com/buy.asp?row_id=5354

Enjoy.

 

Thank you for the site RA. Very interesting. However they want 55$ for 4 plugs or 110.00 for a set on the GS4

 

110.00......