Idle Going Crazy

[pwonder]

92 sc400. If the car sits for more than a day, usually when i start it, the idle is much higher than normal and it jumps around as well. Also when this idle is high and i put it into drive or reverse it does drop down to about a steady 1000 to 1100 rpms but thats still abnormaly high. WHen pulling away out of a stop I DO NOT HAVE TO PRESS THE GAS, the car accelerates slowly and progressively on its own. When stopping i have to press the brake harder than usual because of the fact that the car wants to "GO" on its own. Does anyone have an cause of this and what to do to fix it. I dont have the money to play the process of elimination game with this car anymore, so im hoping that someone knows exactly what the prob is...? I appreciate your feedback.

[XDREAMER]

Sounds like to might be a carbon build up on your iac casuing it the idle to be higher then usual or possible your iac is starting to go but i doubt it.. Try taking out your Idle Air Conttroller clean it with intake manifold cleaner and the passage way's in the t.b intake manifold etc.. Then reset your ecu and see if that help's

[UCF3]

you may also need a new throttle positioning sensor(TPS), and have it calibrated. Check engine light on, and is the oil at the right level?

[pwonder]

the check engine light goes on and off, it never stays on for more than a few seconds, and it usually goes on when im cruising at a steady highway speed. i thought that might be from the intake.

Where is the IAC located i havent ordered my book yet, im thinking is near the trottle body but with this car who knows??? are there any good sites out there that describe or show in detail where these parts are located in the engine compartment.??? how about the tps???

Any help someone can give im greatfull. This car has sucked the life out of my pockets!! But i still love her!

[GrnHrnt]

the check engine light goes on and off, it never stays on for more than a few seconds, and it usually goes on when im cruising at a steady highway speed. i thought that might be from the intake.

Where is the IAC located i havent ordered my book yet, im thinking is near the trottle body but with this car who knows??? are there any good sites out there that describe or show in detail where these parts are located in the engine compartment.??? how about the tps???

Any help someone can give im greatfull. This car has sucked the life out of my pockets!! But i still love her!

My local Autozone parts store will read any OBD codes your check engine light wants to tell you about, for free.

Also you can download all technical info you want for $10 a day from: https://techinfo.toyota.com/

[schott1984]

I did the techinfo thing, downloaded all the technical info for my car in one day. Well worth the money.

[pwonder]

autozone told me a 92 is too old for their OBD

[pwonder]

when you say 10$ a day are you saying you cant save the info on the computer or print it out???

[GrnHrnt]

Like schott1984 says, you can download, save, printout as much as you want for $10 a day.

OBD I codes before 95 are not consistent for maker to maker. Autozone may read a code but they don't know what it means for a '92 Lexus. https://techinfo.toyota.com/ may tell you what the unknown code from Autozone indicates.

Or call your local Lexus dealer and ask if you can pay them a diagnostic fee only, to find out what your check engine light is telling you? Then fix it yourself or go someplace cheaper than the dealership.

[schott1984]

Somewhere on here there's someone saying which pins on what connector to jump to get the codes without the machine. Search for it I guess.

[SCRider]

Wow I have the same problem with my 92. After I changed the plugs, cap, rotor, belt, and alternator, my car started to do the same thing. Idle went crazy, and my acceleration was hesitant. I took it to the shop and they said it's my PCV valve that's bad and why my idle was going haywire. Then the mechanic said that the lagging on the acceleration was because I needed a new throttle sensor, so I'm having that done too. All this is costing me way more then I want to spend on it, he said it was gonna be like 300. Does anyone know if this is worth it, because I don't want to be spending all this money and still have the same problem. Please Help!

[SCRider]

Ok I've been having this problem for a week now and almost spent way more than I wanted to. Someone PLEASE help me. Ok from the start, sorry if this is long but I REALLY need help. My alternator died about a week ago and so I fixed the power steering leak, then after that I changed the alternator, spark plugs, distributor cap, rotor, belt. Then my car would hesitate when I step on the pedal, after that I took the car to a local mechanic and he said I needed a new PCV valve and Throttle sensor. So I got those replaced too. Now the car runs fine on the high way but in the city when it's going from gear to gear, it seems like it wants to stall out. From a complete stop to when the car starts to move it hesitates more then when the car reaches 30 mph. Now, I'm thinking I need new plug wires cause I haven't change it yet or, I'm thinking the timing is off and I need to adjust that, or is it a different problem...someone please help me, I already changed so many things and the problem still exist. The only thing now is that the trac light keeps coming on too if that helps anyone. I know after this my car will be fine. PLEASE HELP! ;) :o