Hi CL

After my grandfather passed away a few weeks ago, I inherited his 1998 GS400. I figured the best way to get an idea of his vehicle would be to join the forum and get to know other people with this car.
I'm not looking to make huge power (300 hp is more than enough for me) but I do want to know what kind of mods other people have done in order to improve driveability.
For some background, I had done a lot of commuting with my previous vehicle and would love a way to improve my mileage in this GS as well. What kind of mods have other people done to improve mileage?
Also, what tend to be the high-maintenance parts for this vehicle? I'm a mechanic by trade and want to know what I should be ready to service most frequently.

No mods will improve mpg.. Had my car 17 years since new and its not gotten any better. The only thing i know of that might improve hwy mileage is a Supercharger but It will lose mpg on the low end so its a wash. Same.

My honest opinion, just drive it and enjoy it. Be Careful with your mods.

Thanks a bunch for the quick response!
I tend to be a hypermiler with my '94 Camry, so I get around 25 mpg with it. I've seen that this car does about 20 mpg. Maybe I can do around the same.
Can you suggest any mods that improve reliability, or maybe identify some of the parts that wear out the most frequently? I'd love to get to work on this and want to know what common mods are.

Well, there is probably at least 20 years of info on this forum for you to read. I modded my car for the best it can be without going too overboard to stay reliable and going faster. This car is one of lexus's best model ever made, I don't know how you can improve its reliability, its already one of the best Lexus ever made. I modded my car 13 years ago, no problems but I was extremely careful and research all of my mods. Depends on what you want to do exactly. Do have performance goals or mpg goals? When my car was completely stock i can get 28 mpg hwy (before that ethanol crap) now i'm around 24-25 hwy, still awesome for a V8. I don't see anything improving its mileage besides not driving it.. (Its already reliable just keep up with its maintenance and you''ll be fine.. I've met people in the 500K miles.. Whats you mileage?

First off, welcome to clublexus and sorry to hear about your grandfather. The weak point on these cars is the front suspension components, especially the lower ball joints and caster arm bushings. If you keep up with that stuff and timing belt, you should be good to go for awhile. How many miles and what color is your gs? Also at the top of the page there's a stickies tab with FAQ's in it that has lots of great information.

Spectru basically covered it... lower ball joints is the Achilles heel of our cars but other than that, normal maintenance will cover you for a very long time.. many members have hundreds of thousands of miles logged and the car still doesn't skip a beat...

Read this forum, it will be your best resource.
ALL original rubber suspension components are shot...replace them

Including the sway bar bushings; for me, I just replaced the originals yesterday, Finally, *****en finally my 98 GS400 rides like a dream...

Welcome to the forum. The GS400 is highly respected here. Post pics when you get the chance. It is not the best handling vehicle from its time, but it is easily the best riding vehicle.

You can do a few minor mods dropping it about an inch or so. But if you go further... that will turn into an addictive money pit that scrapes its wheels and tires and its under-body.

Basically the car is very fast out of the box. Don't know where your at with street presence but these days it's an aging car nobody pays attention to. Who cares. It will run forever.

When i had my car i got 19 mpg mixed driving but if it was all highway it would be around 22-24 at 80 mph. Performance wqs good for its time however theres not huge support for making these cars faster. If you want a fast gs you would be better off swapping for a 2JZ.

Its a known issue to many who have said the Front Suspension and Lower ball joints are bad. I couldn't verify personally that's really true or not. I've had my car 17 years now. (My car is well-taken cared for) I have my Ball Joints checked every time its in for Service) My Lexus Master tech has a GS430 too so he's knows this model GS inside and out. Every Time, it was checked I asked, how was it? He says, "Perfect, in good shape". I have a 2nd GS which is 11 years old now. Same thing, Great shape no issues with ball joints.

The reason, I making this point is I'm also in a Regional Lexus Club out of Atlanta, and have a few friends who own many of the same 2Gen GS, non of them yet has had to replace a ball joint.. So, though its "a heard issue" with those who have reported Failed Ball joints and bad suspension. I and my friends have not. (Maybe because we live in the south) and that we take extreme care of our cars. Though most of us bought our cars "NEW" and have babied it from the start.. I can't testify on behalf of the ball-joints failing.. Owners who bought their cars used, maybe, if was abused and not taken cared for as well as ours in the South. I've seen pics of an ball joint Fail and its not pretty..

What I'm saying if the car is well taken cared for, The OP's grandfather probably babied the car and now he has a minty older GS. I would have them checked, no need in replacing parts that are fine.. My Car is 17 years old still on Original Ball joints and its still perfect so I don't get all the Hoopla about the Fail BJ's. Take care of your car and it will take care of you. Keep it maintain and don't cheap out.. Take it to Lexus and let them do the full inspection every major interval.

Have fun with your cars Gentlemen..

A little off subject. I have a 1994 Camry also. A 4cyl. It is my favorite car over my past Lexus cars the 1999 GS400, 2002 GS300, 2001 LS430, 2005 GS430 and Current 2007 GS350. All those cars were and will be traded/sold but not my Camry! She will stay in the family for many years. She will continue to be pampered to last. Only 210k miles on her.

All things suspension first has never failed me. I'm not saying just shocks I'm talking all suspension components. Suspension, fluids, air/exhaust components, then start modding.

You'll see folks dropping money to make the cars look nice but they handle and run like **** cause of priorities... a stock gs running and moving like new is always better than one on maxed out coilovers with a bunch of replica parts but an expensive set of wheels.

Do it right the first time and you will save a lot of money for quality stuff. Slow and steady ... Since you are new here the best advice is just reading up on the sticky threads first and then you will cover most of your questions.

Start with maintenance. All fluids, belts, etc.

Then go for the small mods....tints...LEDs, maybe some nicer rims.

OP don't listen to 1QWKGS lol. It's well know that the suspension on the 2nd gen is the weak point of the car. There is 18 years of data to back that. Also if you don't believe, search LBJ's or lower ball joints and see the horror photos of owners who didn't replace them. The 98-00 models lbj's are VERY prone to snapping at low to medium speed. I suggest that you at least replace those ASAP. Read the sticky above. It has all of your answers you seek.

yes thats a great idea for a start !