So I just completed my carPC install (finally, phew), and have neglected my 1999 SC400 for the past few months because of it. So I've decided I'm going to do a COMPLETE maintenance overhaul in the next little while as I'm over 160,000 miles and I'm due for a tune-up!
Here are the symptoms my car is exhibiting and other common issues:

- vibration at various rpms, but mainly around 2k. Occurs while in Park or Drive. FIXED: Tranny Mount
- loud engine/noise during acceleration and the engine can be heard while driving normally. FIXED: Tranny Mount
- squeaking/creaking front end.
- creaking in the breaks? when I put it from P to D/R.
- uncomfortable/noisy overall ride, lot's of engine noise in the cabin (very unLexus-like). FIXED: Tranny Mount
- truck shocks COMPLETED (StrongArm from Lordco)
- passenger window regulator/motor? seems like its about to die. Window barely makes it up. (New thread I read says a coating spray on all the moving parts might work)

The Lexus quality ride should have none of these symptoms! The ride should be ultra smooth and quiet with no vibrations, no engine noise or anything like that (xcept obviously under heavy throttle).

My goal is to have the SC ride like new from the factory, or as close to it as possible..
So, with CL's help I want to fix these maintenance issues! Most of the issues I have already researched here (Hell with MODS, is you car RUNNING right?) and here (Carson Toyota/Car rides like new by OLT) and think I know what needs to be replaced.
Second thing I need from CL is where can these replacement parts be purchased for a good price!? Some of the threads that I've read are really old and the various mentioned sources either dont sell the parts anymore, dont exist, or the parts are really expensive. I KNOW you guys know where to get these things for a good price!

So here's the checklist of parts that I will be replacing:

- spark plugs (what kind? NGK? some other type of Iridium? Where's the best place to buy them?) COMPLETED (NGK)
- air filter (Stock? or K&N? BFI?)
- fuel filter
- flux-capacitor
- timing-belt/serpentine-belt
- complete fluid change/flush (oil, transmission, break fluid, etc etc)
^ most of the above should take care of the noisy engine, especially under acceleration.

- engine mounts & tranny mounts (gonna keep this stock, but where can I buy it for a good price?) Tranny Mount COMPLETED
- flex-coupler
^ this should eliminate the vibration and make the car smooth as silk!

- Dazien/TM Engineering control arm bushings (either one better than the other? Where can I get these for a good price?)
^ this should eliminate the front end squeaking/creaking in the front end.

- passenger window regulator/motor eventually.
- new tires (I am a complete newb when it comes to tires, I'll have to research tires more. I plan on getting a nice rim/tire combo somewhere but want a nice comfortable/quiet ride.) New Michelin tires installed 11-08-01
- new battery/upgraded alternator for carPC Upgraded alternator installed 11-11-07 and New Interstate battery installed 12-25-01
- Gixxer_drew Bilstien-Hypercoil custom suspension in early 2013.

Please chime in with additional things that I should replace during a complete maintenance overhaul of a car, or any other tips I should know while making my SC new again
'Value Reliability as a Fundamental Virtue of Performance' - member SCV8

 

Looks like you got a great list started. Definitely go with the K&N filter.

 

OK well 1st of there are no cap, rotor's, or wires to replace in this car. 2nd if a cylinder is not firing cause the coil on that cylinder is bad. Then not need to replace the coils. these are coil over plug motors. NGK iridium/platinum, eather one or shell out $100 for the torque master plugs from carson toyota. Do the K&N stock replacement or I think HKS makes a stock replacement too.

 

^ ok thanks for that. Sry its the first V8 I'm completely servicing. This is the exact type of info I need..

 

The creaking in the brakes from P to D/R is probably the lower control arm bushings. which is probably the other creaking from the front end. Have a friend watch the wheel when you put the car in R, roll back hit the brakes & have you friend tell you if the wheel shifted toward the front of the car. If so the bushings are out.

 

DON'T do the k&N filter.
they are worth about three of my pubes, if you care what an air filter does.
you want maximum filtration, and still good flow. go apexi.
See here:
http://www.mkiv.com/techarticles/filters_test/2/

 

So can I buy an Apexi stock replacement? Or do I have to go BFI?

 

the apexi comes as both a cone filter and a drop-in.

 

So I've just replaced the old Autolite sparkplugs with NGK Laser Iridium ones. The vibration didnt go away as I had hoped, thinking maybe it was a bad plug causing the vibration.
Any suggestions on what maintenance thing I should try next to try to solve the issue? I'm thinking probably bushings..?

 

Could be bushings. It could also be your motor mounts.

 

^ forgot to mention the mechanic that installed the spark plugs said the motor mounts are ok. He asked me to put the car in gear, press the break pedal and give it some gas while he looked at the engine. I thought it mighta been the engine mounts as well.
Maybe the tranny mount? Almost seems like the car vibrates the most at the top of a gear right before it goes into the next gear. Any way I can check that without jacking the car up?

Also, had a CEL for a bad cat that went away with the new plugs. Would installing new plugs have fixed this? The mechanic that installed the plugs looked at the exhaust and said that the one side isn't working as well as the other, which probably means it is clogged. Could this be a reason for the vibration? Some back-pressure or something?

 

If your plugs are firing better your fuel burn will be more complete and therefore there will be less hydrocarbons for your cats to deal with.

 

How does it idle. Does it sound like it is missing? Could be a bad coil. I am a little confused at the post above. This motor has 2 distributors. So thats 2 rotors. It has spark-plug wires and it has 2 coils. One on the top of engine and one down about the 4 o'clock position on the drivers side. I just replaced rotors and wires. The caps were still good.

I wrote all of this without paying serious attention to the year of your car. The 99 still had the 1UZFE correct. I know that in 96 HP went up, but did the motor lose plug wires caps and rotors that year?

 

I was thinking the same thing, but wasnt too sure about how that all works. Makes sence though..

Ya the vvt-i's in 98+ didnt have those components.
The car doesnt appear to be misfiring at all. Everythings fine up until about 2k rpm when the subtle vibration starts. I think I've eliminated a bad plug(s) as the problem, now just trying to decide whats the next best/cheapest thing to troubleshoot..
Tranny mount? Cat (even though the CEL is gone I should still probably replace it)? Or bushings?

 

sounds like tranny mount from your description. and oem cats should last the life of vehicle. check your exhaust gasket right after the cat there could be a leak there that will throw a code for cat inefficeincy