ISRydr

ck, although I have a 99 LS400, I've been going through the same issues for about 3 years now. Sometimes it would die when I stopped at a redlight. There were times the idle would be so low it would die when put into gear, other times it would only idle 300 rpm and at other times it would idle at 600 rpm which is still low. Never once was there an error code. Only recently did it begin to lose throttle all together and usually happened within a mile or so of starting up first thing in the morning. Everything would be fine then the check VSC / VSC off light would come on and the idle would jump to 1200+ and I would have no trottle the first half of the pedal. I began to notice a whirring noise that was coming from the throttle body motor, so I took it to my mechanice who checked the ohms and used a stethascope to determine the throttlebody motor was in fact going bad. I have recently purchased a good used throttlebody and am having it put on 2 days from now. My mechanic assures me this was the problem I've been having all along. I too thought for a long time it was the ECU but thankfully it seems to been elswhere. I will post my results here once it's been installed and ran a few days to confirm but at this point I think I've finally found the culprit. Don't overlook the TB motor as being the issue. Good luck with your search for the problem

Ahhh...makes sense now Steve. I will pass this info on to my mechanic, who probably is already on top of what to check for, but it never hurts to be involved. Thanks again!! Merry Christmas to you and yours!!

Thanks for the info Steve. I was watching when my mechanic pulled up the code and his scanner actually said it was a Throttle Control Motor Lock Malfunction. I've not been able to personally determine what that means exactly and because of the whirring noise coming from the cone shaped attached to the right of the throttle body I won't take a chance by taking on a trip through the Christmas holiday for fear of getting stranded. My question is, with the noise I heard coming from the motor or clutch is that repairable? Or does that signify my potential need to purchase anouther throttle body? I've seen prices for a new throttle body and I'm panicking thinking I'll have to shell out that kind of money then add labor etc. I haven't been able to locate a used TB that visually looked like I would take a chance and buy it. Is there a source for good used parts of this type? I really appreciate your help!!

First let me Thank everyone who contributes to this forum. Without all of your help guys like myself would be in a world of hurt. I do paruse this forum for hints and tips but unfortunately I don't post until I have issues or problems and I'm back with still yet another problem. I have owned 3 Lexus' in total, the first two, a 95 LS400 and a 01 LS430, both were amazing cars and I"m totally a Lexus freak. But I currently have a 99 LS400 that has been a pandoras box of problems for me and I'm not sure the end is in sight. I've had throttle and idle problems since day one and finally was given an error code of P1128 which I'm told means Throttle Control Motor Lock Malfunction. The cone shaped attachment on the right side of the throttle body was making a loud whirring noise the other day and with the motor running I tapped it with a wrench and the idle increased and the whirring ceased. My mechanic, who is a Lexus certified mechanic, said he'd never seen that code and would need to do some research before telling me what needed to be addressed. I'm concerned that I will have to replace the whole throttle body. Does anyone have experience with this code? and if so could you share what I can expect? Thanks in advance for the help!!

The error code that found is P1128 which I understand means Throttle Control Motor Lock Malfunction. Of late I'm hearing a whirring noise from the cone shaped attachment to the right of the throttle body. I hope it doesn't mean I've got to replace the whole throttle body but if I do any ideas where to buy a used one?

I have a 99 LS400 and that's been having intermittent issues with the orange VSC Off light coming on at which time I loose all throttle and the idle goes much higher than normal, around 2000rpm. This issue has been going on for over a year now and the frequency is becoming more regular. It happens within the first couple of miles of driving after first starting it from an overnight sit. So far I've been able to pull over, turn it off, then restart at which point I once again have throttle and proper idle rpm but the VSC Off light stays on for several miles then turns itself off. I'm concerned that this will happen and will strand me when I'm out of town and I travel often. I've had it to the Lexus Dealer and my local mechanic but to date nothing has been determined to be wrong. Has anyone else experienced this type of problem? Or does anyone have an idea of where the potential problem might be so that I can at least be aware of how to discuss this with a repair shop in the event I get stranded? Any help would be greatly appreciated. Thanks in advance for your help!

Thanks for the suggestions. The idle issue came to existence about a month after the 90k service. I hadn't thought about the battery being an issue as the problem is intermittent but will check it out. I took the car to my local Lexus dealer and of course it ran perfectly and nothing was found. Although it doesn't die often I agree it's a huge safety issue. And I agree that turning on the a/c does keep it idling correct but I really want it fixed right. Guess I'll have to wait until it shows again then get it back to the Dealership. Thanks to all who replied. Rydr

Have you checked the battery to tell if it was good? I've never bought a new battery that was bad but the clicking sounds to me like the battery is low on juice. Just a thought but I would check it out if you haven't already. Good Luck!!

First let me start by saying that my 99 LS400 in question is my 3rd LS in the last ten years and I'm a Lexus LS fan through and through. I bought this car a couple of years ago and have had a problem with it idling correctly for a year now. Which I should add began within a week of having the 90K service with timing belt, plugs, wires and water pump replaced, The problem is that occasionally when I'm driving and come to a red light the idle will sometimes fall below 300 rpm and will die while in gear. But the problem is sporadic, at times when starting the car, cold or warm, the idle will not get above 500 rpm when in neutral and when I put it into gear I must apply a little throttle just to keep it running. I've replaced the fuel filter, air filter, O2 sensors (front only) cleaned the MAF, had the throttle body cleaned (while still on the car) etc. etc etc......I'm at the point I need the experience of those familiar with the LS400 to chime in with thoughts about what else I need to check. There is one thing I've read else where that indicated I may need to clean the IAC Valve (Idle Air Control) but I'm told that's a time consuming job and want to know before I take it to my mechanic if I should have them check anything else. This idle problem is driving me crazy. There are times I can drive it the whole day and the idle is perfect, or at least close to perfect, idling around 700 rpm, be it in gear or neutral, without change. As of today it idles at 4 to 500 rpm in neutral and drops to 300 rpm or less when I put it into gear. By the way, no errors show up on the ECU when it does this other than the occasional error code showing a front O2 sensor is bad (both are new) which isn't so. So a reset and off again until another check engine light comes on. When it does it will go off by itself in a day or so. Any ideas would be greatly appreciated. Thanks in advance for the help and great forum to massage for info. Rydr 95 LS400 ( Best car I've ever had) 01 LS430 99 LS400