Idrive70

Hi,

I am new here. This is a great community and I've learned enough to do some modest DIY on my SC 400.

Please advise. I'm seeking a mechanic. Ideally, someone who is qualified and "works on the side" or has a home shop, etc. would be ideal. I'm just aiming to keep the costs reasonable as I can't afford "dealer" pricing. Please offer suggestions from someone in the Charlotte vicinity. I'm willing to drive a bit, so Rock Hill, SC, etc. is fine. Anyway, I would welcome the chance to find an honest mechanic who is experienced with older SC 400/LS400 as I know they have their own "quirks." I know some ace mechanics "work on the side" and are often the most experienced mechanics.

I realize this is more a DIY inspired community, so IF anyone here would be willing to take a look at it and offer some input, that would be ideal. The car is driveable.

My car has a number of minor issues, but right now I'm experiencing the following:

1) Hesitation. This JUST started and has me concerned. And, you can feel it and even hear it through the muffler--you know the slight sputter and shake. It's driveable for certain.
It's like a low level muffler rumble and running slightly rough even at idle. When pushed it will move with reasonable pickup. I know what it's like when I lost the entire driver side
ignition coil functionality--then you're running on 4 cylinders--it's NOT like that.

2) It's had an intermittent problem revving up/down/up/down. Might show up every two weeks, might go away in 5 minutes, might stay for hours. VERY intermittent.

Anyway, I would welcome the chance to find an honest mechanic that is experienced with the SC 400/LS400.
If anyone out there is experienced, and they don't mind, I'd be willing to drive over and have you take a look at it just to rule out something "obvious," before rolling over to a mechanic. Thank you.

FWIW, I don't drive a lot of miles per year and in the last two years I've done the following:
DIY full tune up--about 2 yrs ago inc. plugs, rotor, dist., wires, although two old wires remain
driver side ignition coil about 2 years ago
passenger side ignition coil = just a few days ago
head gaskets, replaced at time of tune up
cleaned air filter
fuel filter
removed throttle body [caked in carbon], cleaned thoroughly, re-installed; about 2 years ago
transmission drain and refill---still a slow leak
new PCV valve--a few weeks ago
timing belt and water pump replaced
AIC--removed it, cleaned it thoroughly, re-installed
MAF--tried to clean it; it "died" and replaced with a used unit. Seemed to work fine.
TPS--never touched it. But, I've read it can impact issues described.
Seafoam. I've run it through the air intake at least twice in the past 3 years + a couple of times in the gas tank.
Berryman. I've run this in the gas tank twice.

I think that's all that I've done which might be relevant to the issues mentioned. I also have a slow oil pan leak. I added a can of Berryman fuel treatment as a "just in case."

Thank you.

note to moderator. I did cross post this in regional section. I hope that's okay. Thanks.

Bankswood

IDrive70 it sounds like you have done quite a bit to alleviate some issues. Before you throw anymore parts at it you should do the fuel pump ECU mod. It solved my problems which were similar to yours. You mentioned you did a timing belt change. Are you sure you got the timing right? If it's off it can act sluggish and lack power. The TPS is an expensive part to buy if you are not sure that's the problem. I have a good spare we could swap on to see if it helps. I live in southeast Charlotte off Carmel road. What year is your 400?

Idrive70

Hi Bankswood and thank you for the reply.
I sent you a PM.
It's a 94. No, I have not done the fuel pump ECU mod.
If you're offering to get together to take a look at it, then that would be great. Thanks. Anytime that suits your schedule. I'm supposed to be driving two hundred miles this weekend, and it's not looking promising.
Yes, the TPS is quite expensive.
Thank you.

Bankswood

I drive I got your pm but I can't seem to get one to you. Send me an email.
Bankswood@gmail.com

Idrive70

I just want to give a shout out to the community and a big "thank you" to Banks.

The immediate issue is resolved and Banks was extremely helpful.

However, I'm still experiencing a revving/hunting issue.
I will post about that separately.

Idrive70

I'm rather surprised there aren't more independent mechanics that specialize in Toyota and/or Lexus in NC/SC area.

Idrive70

Still seeking a mechanic if someone is reading this thread. Thank you.