Hey guys, yesterday night, i noticed my 97 SC400 was idleing a bit strangely. The cars got about almost 40,000 miles on it. Anyway, i noticed when i came to a red light, the car was giving a bit of a shake. Like a quiver if you would. The kind of shake when the car is idleing a bit too low. I was watching the rpm gauge and it was idleing almost near 0. Then when i started moving again everything was fine. The next right light it started idleing low again. It didnt always do it but occasionally it does. I have no idea what the problem might be right now but instinctively, the first people i would come to is my fellow SC community. You guys got any idea what might be the issue? i love this car too much to let there be anything wrong with it!!!

 

Sounds engine related.

 

Yea lol, i coulda figured that out on my own but seriously, any idea what exactly it could be and what i would have to do to repair it? Could it be a fuel pump or some sorta regulator?

 

how much gas you have in tank when problem occured.try some lucas fuel additive

 

Assuming motor is just fine, I would start by looking for vacuum leaks. Other than that, its hard to tell without a check engine light. Maybe even just doing a little maintanence, spark plugs, wires, oil, etc.

 

So i thought it might be dirty fuel injectors, i bought some fuel injector cleaner and put it in with a full tank of gas. On my way to san Diego from LA, the cars battery light turns on, i pulled over and checked the battery, connection seemed fine. Bit later down trip, my radar detector starts signalling low voltage. Little bit later, my lights start flickerring and just as i got to school, the car turned off completely. Im hoping that its just a battery that needs replacing but i fear that it may be the alternator. The battery is a cheap as Triple AAA battery so im hoping its that. Anyone have any idea. The cars only got not even 40,000 miles. Could it really be the alternator?

 

The shaking certainly isn't normal, but the engine normally idles really low when its warmed up and your stopped at a light to conserve gas. This was probably the trick Lexus did to make the 1UZFE much more fuel efficient compared to competition at the time. My engine somethings idles as low as 600-700 when its warm, unless I have the A/C on. The thing is that the gauge is really deceptive. The first notch on the tach indicates the first 600 rpms while the rest of the notches increase in incriments of 200.

your story sounds pretty similar to my experience a while back. On a Friday about 2 months, I got my car serviced. Everything passed with flying colors; however, by that night the battery discharge light came on. I called up the Lexus dealership, but they told me the mechanics are busy until the next Monday morning so I gotta wait the whole weekend. This was back when I was working weekends at a job in Framingham, 25 miles outside Boston. Prior to leaving Saturday, I checked the spark plugs and all the connections. Everything seemed perfectly fine with no problems, corrosion, or anything. The light remained on, but the car was running fine. I drove to work and back (50 miles) problem free so I assumed it was a faulty warning or something. I've had that happen before with the check engine light. Then Sunday comes. As I'm driving out to work, the car starts acting real wierd on the highway. The ABS light starts flashing, the check engine light comes on, and everything is starting to dim. By the time I got to the Framingham exit on the highway, the engine is idling really bad, sounding like its chugging on its last sip of gas (even though the tank was 2/3 full).

Anyways, the story ends up the battery is completely dead and my car is dead in the water at my job. I tried jump starting it with my friend's car, but no luck. I ended up staying with my mom overnight and getting the car towed back to the Lexus dealership the next day. It turns out (as I was suspecting) it was the alternator, not the battery. Unfortunately my car ended up draining out the battery's cells down to their low voltage discharge threshold and I needed a new battery too. Grand total was $400 for the alternator and $150 for the battery, plus labor. I also had to pay $190 for the towing since I didn't have AAA.

Unfortunately, if your car is dead like mine was due to the alternator, you'll probably also need a new battery on top of it since it sounds like your car drained yours too. I would first try getting a friend to jump start your car and see if you can charge the battery. Hopefully its not dead and at least you could drive it to a local electrical shop to find the root of the problem. If not, you'll have to get it towed. Good luck.

 

Vac leak I highly doubt is the problem, same as the injectors being dirty. I would check your voltage from the battery.

 

Sounds like a charging problem to me, have your battery checked. Did you ever have a power steering leak? If so, it tends to leak on the ALT and can jack it up. The ALT could just be taking a sheeat anyway since the car doesn't seem to get driven enough.

 

sounds like the alternator

 

The charging issue is 100% the alternator. The battery light indicates that the diodes in the alternator have failed. Thus no charge goes to the battery. The power steering pumps for 92-95 had issues with them leaking power steering fluid onto the alternator and shorting them out internally. Around 1996 they put a plate above it to prevent that ,but it doesn't work if the pump leaks a lot. The battery ends up running the car till it is sucked of all its energy. Then when the car is ready to die it goes crazy flashing dash lights ,check engine lights,lights you have never seen turn on before lol. The car's ECU progressively turns things off that aren't important like a/c the radio etc. For the idling issue it is motor related. Not the fuel pump or the injectors there is a good possibility that it could be a vacuum leak or your IACV. The Idle Air Control valve controls the amount of air when your sitting at a light. After driving your car for so long dirt and other debris builds up and then it gets clogged. They have links on how to clean it out its not hard at all. Get some throttle body cleaner open the throttle plate(s) spray it in then wipe it off with a rag. That or you may need to adjust your TBS (Throttle body Sensor) and loosen the screws to raise your idle up. That is if the cleaning does not help. Good luck

 

Whenever a battery light comes on in your dash it means that the car is only operating on battery voltage and the battery is not getting charged by the alternator. Most of the time it requires a new alternator but alternator wiring should not be left out of the equation.

As for the rough engine, +1 for a small vacuum leak. The injector cleaner might have helped a little bit, but it sounds like the engine is running lean overall. Look around on the intake manifold for all the little rubber hoses coming out of it. Look for any that are cracked or loose and replace the hose as needed. The little rubber hoses you can get cheap at any auto parts place and they can have them cut to length or colored if you want to go that far. If the hose doesn't fix it I would look into an idle control problem.

 

Wow guys, nail on the head, thanx alot to all of you for your responses. I really appreciate it more than you guys could imagine. I barely made it today to the autozone just as my car died in the lot. They checked it out and said it was definitely the alternator, and just as Brendon said lol, it drained the **** outta my battery so im gonna need a new battery too. Alternators around here cost about $350 in San Diego but thats way too expensive. I had the battery recharged and i picked up a second battery. Im probably going to not drive the car until friday and just head back home from school friday. Once the recharged battery dies, ill just swap it out with the new one and this should get me back to LA so i could have it repaired at my uncles shop. I talked to him and he said he could pull a few strings and find me one cheap. As for the idle problem, thanks alot for the info., ill definitely have the throttle body and valves cleaned out and see if that does it. Im thinkin its because the car hasnt been driven enough and thats whats leading to the problems im having but i guess thats better than it having problems from too much driving lol . Anyway guys thanx alot for the help, its much appreciated!!!

 

Not sure how far you're gonna get with those 2 batteries. SD to LA sounds like a pretty decent drive. I'd invest in a AAA membership..

 

Yeah man your car might last 15 minutes at the most I would not recommend doing that. You will end up dead in the water. If your feeling lucky keep everything off electrically when driving there. Look on CL for a alternator or put up a wanted add. It might be used ,but it gets you by for the time being. Ehh giving you options.....