Couple questions: First, does anyone know what's the best spark plugs to use when replacing the old ones on a '92 ls 4? Is fuel injector cleaner needed if you use premium gas and if so, what kind?

 

you can use ngk iridium ix and what not. but if anything i would stay stock denso platinum plugs. unless one is cheaper than the other so on and so on. i doubt you willl need fuel injector cleaner since your using premium gas. maybe once in a blue moon. depends on how your plugs look and everything.

 

Using premium fuel does not guarantee a cleaner engine. It's not the octane rating that keeps your engine cleaner. It's the fuel additive that does it. In most cases, the fuel additive is good, but it's not going to clean an already clogged or dirty injector.

My car 98 GS400 has seen premium fuel all its life and when I did a fuel injector cleaner, lots of carbon came out of my exhaust. The difference in fuel pressure before and after the run was enough to convince me that my injectors were sort of clogged. My car gained about 4 mpg on the highway and 2mpg in the city.

 

I heard the only good fuel injector cleaner is the "LUCAS" brand cleaner? Is this true? What are some good brands? What did you use GSteg?

 

I used Lucas

First time I ran it through the fuel line using a fuel injector cleaner canister. You hook it up to an air compressor, mix fuel and the cleaner into the container, set the pressure, and then run your car.

2nd method I used was to run the car until the gas light goes on. Then I pour in 1 quart (yes a quart for about 2-3 gal) and drive it for another 20 miles. You'll get quite a bit of smoke coming out whenever you turn on your engine. I've had carbon smoke coming out of my exhaust for about a week Dont buy those small 5.25oz bottle. They cost a lot when a quart cost only $10. I bought a gallon myself because I have many cars at home. It works out to be about $7.50 per quart ($30/gal). The recommended 2-3oz per 10 gal is too diluted to do any serious cleaning. 2-3oz per 10 gal is great for every time you fuel up your car to maintain a clean engine.

I went from about 18-19mpg highway to about 23-23mpg............

 

what kind of fuel injector cleaner did you use?

 

..............

 

So you used 1 QUART of Lucas per 2-3 GALLONS of gas??

 

Yup. ..........

 

MAN! That seems like a lot lol. Didn't throw any codes or anything?

 

No. No codes. If you're hesitant, then run it with 5 gallons.

Keep in mind that when I ran the lucas through the fuel rail via canister method, I had a 50/50 ratio of lucas and gasoline. That was WAY more concentrated than the 1 quart per 2-3 gal. My car ran fine and it idled fine.

 

does it do the same effect if u just put a quart in the gas tank? or u need to do the canister method?

 

Both methods gave out a lot of carbon smoke through the tailpipe. It's the same effect except I could run a higher concentration through the canister method, and I can get faster results because I dont have to wait until the whole gas tank runs out. I've done this for many cars and none of them threw a code. All cars I've ran it through got higher fuel economy.

 

The first method seems difficult to carry out from the eyes of a person who has never done it before. I would like to carry it out, because it's faster than the fast method. If you would, what's the step by step process for the fast method for a beginner?

 

The 1st method isn't something you do by yourself unless you have all the necessary tools. It's not wise to invest in the fuel injector cleaner canister for a once time use.

Buy a quart of lucas fuel injector cleaner. When you're down to about 3 gallons (usually when the gas light comes on), dump the whole bottle in without refueling. It's okay to pour in the bottle without refueling. Then just run the tank down as much as you can without running out of gas.

But beware. Smoke will be coming out of your tail pipe within a day or maybe on the same day. There will be lots of smoke if your engine is kinda dirty. It took me about a week before I had no more smoke coming out. Everytime I start my car in the morning, there would be a large puff of smoke coming out . But during the drive, you dont really get any smoke so it's not like the car shoots out carbon smoke all the time, just mainly at startup.