SC400slide

iTrader: (11)

It might sound dumb, but it may be your TPS that isn't set to spec. Also could be the drive line that is loose. What ended up being my issue was the TPS that was not set to spec. I was so sure it was mechanical, but it wasn't. It's a pain in the you know what to set the TPS to spec with an ohmmeter, since the TB is in the rear, middle of the engine bay, hard on the "Patellar tendonitis", and your back.

I know it's frustrating to hear when you have the car apart for something else, I would replace whatever you are replacing now and see if it fixes it, then, if nothing else suspicious is visual, I'd check the drive line cable, than the TPS.
GL

canucklehe

it only seems to happen at just the right low rpm, then accelerate and you get the clunk. was your's the same?

SC400slide

iTrader: (11)

Mine was, accelerate, decelerate, small clunk every time.

Bdub215

iTrader: (1)

Get two new lower control arms and ball joints (under 100 bucks) and let us know how the car drives afterwards.

canucklehe

are the balljoints already pressed on the LCA? where do you get them? my car has about 142K miles. do you think they'd be that worn at my mileage?

Sc400slide, did you adjust TPS yourself? I assume "TPS" is throttle position sensor. What is "TB" ? What is driveline cable? I am quite mechanical, just haven't heard of those items.

FWIW, I pick & choose some jobs. I only had mechanic do front motor mount as he was doing the Y pipe and I figure hoist & heat make that job waaay easier instead of laying on my back from underneath and snapping old exhaust bolts,

SC400slide

iTrader: (11)

I did adjust the TPS myself. I used an ohmmeter, and screwdrivers. The procedure is tedious,but not really hard. Where the TPS is, connected to the TB, is a hard place to access under the hood. Besides accessing, it's a cream puff.
Yes, TPS is the Throttle position sensor. I just figured out recently that the SC400 has 3 "TPS's" in it. the throttle position sensor, the tire pressure sensor, and the tilt position sensor.
Throttle Body.
The driveline cable is what powers the acceleration of the vehicle. I don't know if there is another term for it. It's above the TB under the black plastic cover. Sitting beside the driveline cable is the cruise control cable, that could be loose too. If any of those have slack, use the bolt located on the cable to tighten it till there is no slack.

Most job's, I try to do myself. I'm expecting the starter to go out on my SC (starter bearings are making noise), so I have a new starter ready up in my closet. It might take a while for me to replace it, because on the V8's the starter is in the middle of the motor. I was recently replacing the bank 1 o2 sensors, and while I was at it, I removed the Y-pipe assembly. It was a pain, but I was able to replace the exhaust gaskets. If the job put's your back and knees in jeopardy, don't proceed to attempt! Good luck

canucklehe

driveline cable sounds like throttle cable (?). you think that being loose would give a clunk?

where did you find specs on what the TPS should read/set up procedure?

another thing mine does is run like a slug cold. within 5 minutes it is fine, but when i leave home and make that first turn out into traffic, i know it will have no holeshot. by the time I reach first stop sign, it's got some oomph.

thanks for your help!!

SC400slide

iTrader: (11)

No no, if you had sluggish acceleration, you might wanna check the THROTTLE CABLE, thank you!

Here are some threads:
https://www.clublexus.com/forums/per...ohms-help.html
https://www.clublexus.com/forums/per...on-issues.html
If your TPS is working, you will be able to set it at 0.00 (infinity). I forgot to add some very important things you need to set the TPS. You will need an ohmmeter, standard and Philips screwdrivers, a feeler gauge, and most importantly, a computer connector, or a TPS harness.

*I must keep in mind that your car that is having problems is an ES, not an SC lol.

TPS could cause this as well, but also o2 sensors, MAF that is dirty, IACV, dirty fuel, the list goes on. Did the motor mounts looked smashed and broken? How about the diff mounts/u joints/any rubber missing?
Hope you solve this soon!

Bdub215

iTrader: (1)

Rockauto.com sells Complete Lower control arms either with or without the ball joint. choice is yours.


My car does that too. Not sure of the cause but i dont push my car when its cold anyway.

canucklehe

thanks bdub. I also saw them on ebay for $100 shipped. I'm going to take it to my alignment guy/friend. He is well expereinced and should be able to pin down so I don't chase the problem with parts I may or may not need. all of your info will help me point him in the right direction if it isn't obvious.
'
I typically don't push mine too hard when cold, but pulling out sometimes it needs the power that isn't there, so i try to pick my spot accordingly.

canucklehe

alignmnet mechanic/friend said my LCA & balljoints were fine. He said dogbone was shot and I replaced it, and it was done. I also noticed it fixed the rattle i got when driving over bumpy road. But it still didn't fix this acceleration clunk. Only happens at lower RPM, like 1200-1500, then accelerate.

I will check the other mounts. how many tranny and motor mounts in total? I've done 2 motor mounts now.

JonnysES

Chances are it's the rear mount. Do you get a clunk thud when shifting into reverse or drive?

canucklehe

I'll check and see but nothing noticeable that I recall. most noticeable going about 30-40 mph, let off gas, rpms drop to 1000-1500, accelerate and thud/clunk.

what's the rear motor mount like to do?