I just purchased a 95 sc400, and when I get up to 40 mph and hold it there it makes a jerk or some type of hesitation. (transmission) It only happens at 40 not above or below. I wanted to ask the board before I took it in to the dealer. Thanks for your Help!

Brian (Atl., Ga.)

Ps. any other good shops in Atlanta besides the dealer?

 

It could be your transmission mount.

 

How many miles does the car have??? Was it purchased from a private owner or a dealer..(Is there any warranty?) There could be a couple of minor reasons....

When my car (74,000 miles at the time)hesitated at a certain speed(45-50), it wasn't the transmission at all it was my spark plugs going/gone bad.(I also changed the wires) Verdict: problem gone!

Possibilities: foul filter, injector dirty/bad, transmission fluid, service trans w/filter, trans. mounts... It's hard to judge... Does the car have good books/records? Also check with Lexus service to get the car's maintenance history. GL

The Ikon

 

My 93 has the some vibrations at around 40 mph, between 37-39 and not all the time. I don't think it is the engine mount. It must be the transmission changing from 3rd to 4th or the torque converter.
Please let me know what you find out with your.

Just bought it 2 months ago at 103K mi. now it is about 107K. I notice this vibration a few days after I got it.

I am going to find out exactly how to reproduce the vibration before taking to a transmission shop. I looking for a reliable trans. shop around my house also. IMO, Dealer and brand name shop are no good at all

 

without driving the car, it could be that your transmission is slipping(very costly $$$). Have you done a transmission service since buying the car? Whats the color of the trans fuild on the dip stick?Feel the oil for small fine metals?

 

It is the egr, if unplug it will stop, this is not a recommended fix however, it will turn on the check engine light and disable the egr system. If memory serves correct there is a gasket problem that is partially blocking the egr passage. Make new gasket.

 

My '92 SC400 experiences the same shiftiness around 40mph. I always figured it was the "intelligent" transmission acting stupid. i.e. couldn't make up its mind if it wanted to stay in a certain gear or not.
It would be interesting to see if the EGR gasket is a fix.

 

EGR gasket. Okay, where is the EGR unit located???

 

Hey everyone!

I just contacted my old mechanic yesterday and had asked him about that problem and for some reason he told me that was the first thing he noticed when he test drove my car. He told me that all he did was just serviced my transmission and lubed or whatever the parts where it needs to be I didn't think that a lexus need a lube job but anyway thats what he said he did to cure my problem. Then again that was for my car so it could be different for yours. He also said that he had retorqued some of my bolts under the car forgot which one more than likely the transmission mounds and ?.
Hope that helps.

Later,
Banking

 

Thanks Banking,

According to the service print out from the dealer, my transmission was service less than a year and the fluid is clean. But I'll look in to it to see if this is the issue.

VQT

 

I've got 130k miles on my 92' sc400. Had the same problem since about 90k. Easy solution turn OD off when not on freeway. My vibration problem only appears when shifing from 4th to 3rd around 35-50mph. When pressing on the accelerator gently right before the gears shift there is about a 1/2 second vibration. Do this sound like everyone one elses problem? I wolud like to try this EGR disconnect/replacement, where is it? Thanks

BTW, I replaced my spark plugs, wires, caps & rototrs, and tranny fluid and I still have the vibration problem.

 

Folks the egr valve will not cause a vibration. On coupes with a decent amount of mileage and a vibration while sitting still and rpm range of around 1500-2000 it is the engine mounts.

 

the only difference in the LS400 tranny and the Sc400 is the valve body...those are different.

Mind

 

I changed the gasket on the egr valve. So far, it has not hesitated or jerked at 40 mph. Nor has it hesitated starting from a stand still. It was a very cheap fix. I went to auto zone a bought a sheet of gasket paper and cut out the temp- plate of the old gasket and put pencil tip holes in it and put it back in and that's it. Lextech thanks for the tip. I'll let you know if it starts the problem again, I sure hope not.

 

bangbang001 ,

Please explain more detail about how did you replace the gasket. Where is the EGR gasket located at? Thanks.