HomerTHX1138

Mine had hesitation at low throttle. Throttle body cleaning helped. A large bottle of techron completed the job.

Same here. Had the non-illumination problem, sent the boards off, got them repaired and now the speedo and tach do not work in the mornings. Once the car gets hot they work 90% of the time.

I have a question: Does the cycling improve mileage? I would think the constant compressor would simply mean a bit more drag, constantly. Also is compressor life affected by cycling versus constant use? Thanks.

If anyone wants a pic of some REAAAAALY dirty ones I can say the ones that came out of my 93 last changed who knows, are filty.

Start simple and cheap - have you gotten the tires balanced?

Updates: Throttle body cleaning (outlined in another thread) fixed MOST of the off-line hesitation. It's better, but not perfect. Distributor caps and rotors were replaced a couple of months ago with the timing belt and other internal work before I took possession. Today I had the fuel filter replaced, the tranny filter replaced, and fluid changed with Toyota Type IV. Issue #1 and #2 are still present. I asked the repair shop (a national transmission chain) to inspect the motor mounts and transmission mounts. They said the mounts were not cracked. They also test drove the car and didn't notice any problems. SO, The spark plugs and wires may still need changing. Are dirty fuel injectors a possible factor? Which dealer service do they change them, if any? Thanks in advance

TexasLexus, My post was a bit confusing. The throttle body was absoutely coated in black gunk. I know for a fact that premium was not run in the car the last few years but I don't know if this contributes to the build up. ANyway, the bugs were on the air filter face.

Same problem here. So replacing the whole tank is the only option? Anyone recommend where to get one? Thanks.

My 93 LS400 139K would hesisitate at low throttle from the line. It would also dive in idle RPMs when the AC was turned off or the car put in park. It also shudders at ~45MPH, and has a vibration and noise when in overdrive or very low RPMs while driving. (the last problem I knew would not be addressed by the T.B.C. and was not) I posted a thread about it and got many suggestions. Today I replaced the air filter and cleaned the throttle body. The result is low throttle acceleration is now smooth and the idle does not dive when the AC is turned on or off or the car is put into park. The album only let me put one photo in so here's the before: It was NASTY. The carbon would come off in thick black crusty shiny spots and a ton of brown residue. BTW, the air filter looked clean but DUH I was looking at the backside when I first opened the plenum. The front side was a study in airborne bugs. All kinds of shiny insects were crammed in - at least 50, along with dust dirt etc.. . I have more photos on the cleaning process / filter comparision (including the one in the engine and the Japanese brand I put in side-by-side), and the after cleaning. Note that my throttle body had ONE butterfly valve. The instructions show two but my 93 has one. Also I would suggest that people performing this plug the first hole with a rag. The second, rearmost hole has a lip around it to prevent stuff from draining into it and I believe the whole assembly has a slight tilt toward the opening of the body. Therefore, spraying the cleaner causes it to run toward that first hole. I also found that a hanger with the cardboard tube proved to be perfect for a tool: The cardboard tube could be used to push rags into the TB and the coat hanger, straightened but with the hook left at the end, was a safe way to retrieve rags from inside the body. The valve and area around the valve are now clean. However, there is still build up back in the plenum. I found it impossible to make the whole "box" clean from that orifice and I spent about 1.5 hours on the actual cleaning part. Basically, you have to draw the line somewhere and frankly I wasn't sure where some of the gunk in the rear of the TB would run to if I managed to loosen it as I believe the box then extends right and left when looking into the TB. That's about it. Bosch Fuel filter comes next. I also bought Jap distributor rotors and caps but found out that my grandmother had these replaced with the seal and timing belt job done less than a year ago. Thanks to Curt for his excellent how-to here: http://www.lextreme.com/tb.htm

Thanks! I do wonder if it is the same problem? Mine won't move at all (in out doesn't work) and it makes the noise which is not mentioned in that thread. [edit]=noise is mentioned later in the thread. [/edit] In any case, this looks to be a great starting point and well documented. Opening it up will at least help me understand what is going on.

Well per earlier thread, just received a 93LS400. I don't this is relevant but just in case it is: I installed the rehabed circuit boards, and returned the instrument cluster to working condition. I hooked the power back up and everything, including the steering tilt was fine. I had it all the way back and down for the cluster install and so proceeded to put it into a comfortable driving position, I moved it in a bit, up some, then back down and noticed it made a weird noise -kind of a grinding or gear slipping noise when I hit the downmost limit. I shut the car off and the wheel moved to the "up and out" position. All was fine until I started it back up: Now the wheel stays in the up an out position. Joystick toggling causes that same clacking/gear slipping/grinding noise -whatever you want to call it - when I hit the downmost limit. It clearly sounds to me like a motor is moving but two units of the mechanism are not engaging properly ie perhaps a gear or link is broken or disengaged. Obviously I did not do anything do the tilt mechanism while replacing the cluster other than to move it to the down and out position using the joystick. I did several searches for this issue and came up empty which worries me as this may not be a common problem or DIY fix. PS - Totally unrelated but I had to replace a corner light that had been cracked. I thought I broke the new one beyond repair (copper contact and bulb popped into the housing) until I read the how-to guide. Excellent resource!

Thanks for the replies. CuMan, Actually that is the primary reason she finally gave the car the boot. When I received the car a couple of weeks ago the dash had basically quit working. I shipped the boards to Jim Walker on Monday and was supposed to get them yesterday but they didn't make it and should be here today. I'll check the records for any fuel delivery related repairs. She claimed she did not save every receipt unfortunately. I can do the airfilter obviously myself and will see about having all the other items replaced. Certainly the tranny fluid drain and top is going to happen first thing. Does #1 occur while accelerating? Not under heavy acceleration, maybe gradual. I haven't had it long enough to say for sure. Again, #2 is not that bad. Something just hit me too that may or may not be related. When putting the car in park with the AC on the RPMs drop really low for about 2 seconds and then return to normal. I wonder if this is a low idle setting? Does the tranny use engine vacuum to operate? OT: Finally I typed that last paragraph's last sentence with difficulty: I just sold my 83 Mercedes 300D which I had driven for years and loved, after I got the Lexus. The one thing that was always flakey on that car was the vacuum and in fact I had the vacuum pump and some valves replaced as a condition of the sale to fix the transmission shifting (clunking on the 4-3 downshift, hard shifts) But that car was bulletproof in most ways.

My grandmother wanted to give me the car but I insisted I give her something SOoo, I got a really good deal ( $1500) on a 93 LS400 with 139K on it. It's been garaged for the most part, serviced by Lexus, and aside from some body work which I'm having done (her vision isn't what it used to be), is in really great shape. She did just replace the AC compressor ($1400!?) and before that in 05 reported a fluid leak for which they charged her about $2500 to replace various internal seals, timing chain, water pump etc... I also noticed that she replaced the steering pump in 99 and read here that it's problematic on these cars. Questions: 1 The car occasionally has a slight shudder, almost a hesistation around 40mph or so. Concerns? 2 When it upshifts to overdrive and is running at very low RPM, there's a bit of noise and vibration. Mind you it's very slight. Possible tranny mount? Other? Or nature of the beast? 3 Finally when given very little gas off the line it also hesitates just a bit. My uneducated guess thinks maybe dirty injectors. Just a bit more pedal and you don't even notice it. Thanks in advance. Overall the car is an absolute pleasure to drive.

I've noticed over several different cars that if the braking is worse while going downhill the rear rotors are more to blame. Mechanics tend to alway say front, front front (rotors). But the rear can and do warp too.