skperformance

iTrader: (6)

Last week i decided to pull my old plugs as they were 2 years old with about 80 000km on them. They looked fine and seemed lean all the way around by white tips.

I got a set locally of 8 for $50 . Which is the same NGK iridium's that were in there before.
The last time i changed them i noticed no difference at all in the car.

This time was drastic difference.
It starts up faster without any mis starts with the remote start when very cold -15.
The mileage has dropped from 9L/100km (26mpg) to 6L/100km (39mpg) in the same stretch of roads.
So what has changed !
I only did one thing differently , when removing them i noticed the threads were dirty . So i knew the head threads were dirty also. Also the ground screw on the coils on each of them were tight also.
So i sprayed pb blaster on each thread before installing them on the plugs threads as well as the screw holding in the coils.

Also the voltage on my add on display for my air suspension shows 14.1vdc at start with only a drop to 13.7 when the engine has reached temp .
It used to show 13.4vdc at cold start and down to 12.8 when hot. I have replaced all ground on the car a year ago as well as the battery so it should have all it needs to flow. My digital gauge is reading the voltage from my trunk which has a voltage drop of 0.3-0.7 volts from the battery up front . It has 0 gauge wire feeding the amp in the trunk so the drop is normal. The battery should be reading 14.4vdc at the battery the way it should be now taking the voltage drop into the equation .

Also had a tranny which shifted with the slightest effort added whether cruising or driving hard it would kick down easily like it was dragging bricks behind it .

So , conclusion , clean the threads properly and replace the plugs , use pb blaster and post the results. I am impressed by far.
Also my unusual mileage has to do with my car being lower with air suspension to reduce drag as well as the tires psi set to 40psi. The biggest factors are my cold air intake , exhaust being freed up and the electric fan which only turns on when i come to a full stop.

Oh yah , i mod it because i love it !

PK_Celsior

iTrader: (18)

hehe i mod my ls400 because i love it too :]. another person using ngk iridium's like me. almost though i was the only person .

sonyman

I think you're pretty damn confused. The next time I change my plugs, I'll be sure to clean the threads for that ultra gas-mileage savings. Or should I add acetone to my tank instead?

skperformance

iTrader: (6)

Never used acetone only seafoam.
Confused over what?

PureDrifter

iTrader: (10)

i think you need to stop being so sarcastic

SK was talking about cleaning the threads of both the plugs and the coils, dramatically improving the grounding connection.

PK_Celsior

iTrader: (18)

ive always heard of seafoam but scared to use that stuff. haha im scared im gona use it wrong and its gona murda my engine ahhhh. maybe i should do it some time :]

PureDrifter

iTrader: (10)

i love seafoam, damned stuff can breathe new life into an engine

skperformance

iTrader: (6)

The first time is always the hardest with seafoam. Once done you'll be doing all your neighbors as it is so easy to save gas and increase power again.

JDMCelsior

iTrader: (1)

Seafoam works! Used it on my SC400 and brought the car back to life. That's all I got to say.

tbilisi79

Whats the best Seafoam product to use? I have no problems in my car now. Just wondering if I can help the motor out in some way?

steveski

Seafoam is 100% safe in the tank. It costs around $6 and is guaranteed to not harm your motor. I have used it half a dozen times and will use it today before I drive from Houston to Alabama. It cleans and evaporates moisture in the tank. So far so good.

BIGBADDAD

I had some problems after steam cleaning my engine (DONT STEAM CLEAN YOUR LS400's ENGINE) any way, I used it and its great. I will use it every 6 to 10K miles. (current milage 242,000) Dont be afraid. I have only used it in my tank, it say's you can add it to your oil..........not sure about that one.
Have a great day.
Mark

PK_Celsior

iTrader: (18)

yea you cant steam clean the ls400 because the water can seep into the valves and what not haha. so never let lexus dealership detail your motor or your done for. i seen a lot of problems like that happenin at the dealership

phy

that happened to my car. I got it detailedl ike 3 years back and they cleaned the engine bay (duno how they did it) but 2 days after I got it back the check engine light came on and the car was runnning really wierd. Turned how they got water into my valves and flooded my spark plugs >.<

skperformance

iTrader: (6)

I wash mine twice a year , just don;t stick the hose in places it does not belong and just dust it the water will not affect it. Also keep the car running when applying water.