Question about 1993 Lexus Es 300

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Hunting on acceleration,ok at speed.

When you give throttle car hunts,bucks and then somooths out at approx 20 mph. Just changed plugs and air filter.where to start?

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Distributor cap and rotor,probably corroded,also,under load,ignition coil(s) may not be producing enough spark-check resistance in ignition coil-

Posted on Aug 12, 2008

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My son's 1997 Baleno GXL 16B idle is ok when cold but when hot idles at 2000 then backs to 1500 to 1000 and back to 1500 then 1000 ??


this is a USA form and we dont have Balenos,
but do have lots of G16b (16valves)
that is called hot idle speed hut, its a software bug, in the ECU.
this same bug cost toyota 2bill bucks in fines. but not suzuki nobody cares. on them.
a barn find car, done many, too many.
That sure can be many things but in order its clear.
THE ISC is failing , in fact its doing the hunting, if you unplug its 2wires, it stops hunting.
the cause is really air leaks, the ECU is programmed to hold hot idle at 800, rpm , if it cant. it ILLEGALLY hunts it.
a lreal car, would just send the valve closed command over and over and not hunt it, as hunting can kill, drivers with bad skills.
First car i saw this on was a 91, Vitrara, Sidekick. G16a.
then a 96 G16b,
you have a vacuum leak.
that is the cause.
and I bet lots more ... for sure, last one like that I did had 15 majors.

Sep 17, 2016 | Suzuki Baleno Cars & Trucks

1 Answer

Engen problem and missing


Sir, your question is not very clear, but I will still try to post a solution here. Engine missing could be due to any problem in fuel system, ignition system, engine or ECM as well.

LOW ENGINE IDLE SPEED (Poor idling):
-Throttle body (do the cleaning and idle speed learning)
-A /C signal circuit
-Fuel pump control circuit
-Fuel pump
-Intake system
-P C V valve (clogged or open) and hose

ROUGH IDLING:
-Cylinder Compression
-Ignition system (Igniters, spark plugs, wiring harness)
-Spark plug fouled, gap too wide or too short. (1.00-1.1 mm)
-Fuel injector circuit
-E C M power source circuit
-Fuel pump control circuit
-Fuel pump (required pressure 44 psi - 49 psi)
-Throttle body (cleaning)
-Intake system
-P C V valve and hose
-Air fuel ratio sensor
-Heated oxygen s ens or
-Mass air flow meter
-Idle hunting
-Throttle body
-Intake system
-P C V valve and hose
-Air fuel ratio sensor
-Mass air flow meter

HESITATION/ POOR ACCELERATION:
-Fuel pump control circuit
-Fuel pump
-Spark plug
-Ignition system
-Fuel injector circuit
-E C M power source circuit
-Mass air flow meter
-Throttle body (do cleaning)
-Intake system
-Valve timing
-Cylinder Compression


Jan 18, 2014 | 2008 Toyota Corolla

1 Answer

Idle up down


hunting or surging ilde. name the 2 RPMS, low and high , is it hot or cold engine this issue.? 400rpm or 1000 or 2000 all are diff.causes.
no year, stated. so cant help.
but ill answer in the generic,
1: the ECU (got a carb,? )
the ecu controls idle speed at all times.
if not , there is a problem (you)
A: air leaks in the induction will make motor race at some point the ECU/ISC loses control. and hunts. trying hard to correct it.
b: egr stuck open idle too low, iSC cant correct it,, bad EGR.
c: engine EFI running way too leak starving for fuel so it hunts for 2 reasons < ISC hunting, and lean does that.
lean is gross power loss and opening throttle bogs the engine.
so is double bad. ISC makes it worse,

all this breaks down to 2 reasons.
1: ISC bad. in some way (gummed up. or restricted inside)
2: bad fueling or air leaks. vacuum leaks.

try answers , the hot cold question and the 2 speeds, of the hunt.
lowest rpm and highest of the hunted range of RPM.

Nov 23, 2013 | Honda Civic Cars & Trucks

1 Answer

Car not get over 20 mph


Check your Air idle Control valve, speed sensor, throttle body , and your accelerator cable. You should find the problem there.

May 17, 2013 | Ford Thunderbird Cars & Trucks

1 Answer

I wish to adjust the idle tickover speed a wee bit on a 2007 Ford Transit 2.2 Duratorq engine. It is currenlty ticking over at approx 800 rpm and is hunting at this rev. If I could raise it a wee as I do...


First ensure that the throttle interior is really clean, a surface layer of grime can upset the ECU's ability to meter and govern the air entering the engine. If the throttle body interior is found to be really oily and dirty check on the idle air control valve and make sure that it too is cleaned up. Next put the ignition switch in position 2 (on, but no start) and depress the accelerator fully and release. If there is an issue with the throttle position sensor this procedure can help the ECU relocate the throttle plate position. Start the engine and if it is still hunting locate the air mass meter (AMM) on the air ducting immediately next to the air filter and disconnect the electrical connection. Does this remove the hunting aspect?... the rev speed might change but for the moment concentrate on the evenness of the tick-over. If the idle is even when the AMM is disconnected but hunts when connected then look at replacing your AMM. Try spraying the AMM with no residue electrical cleaning spray to see if this improves matters.

Dec 02, 2010 | Ford Transit Connect Cars & Trucks

2 Answers

Rpm hunting


check for a vaccuum leak this is where i would start if it rolled into my shop. possibly a PCV valve sticking or a hole in the hose, this hose should run from the valve cover, or crank case and then to the intake, or carb.

Apr 25, 2010 | 1998 Isuzu Trooper

1 Answer

I have replaced the throttle position sensor, egr valve, o2 sensors, mass air flow sensor, fuel system, and my 99 trooper idles high, and shuts off


Check the Idle accelerator valve located on front side of throttle body, it is either stuck or needs cleaning real bad, this is what controls your idle speed, by letting small amount of air in. It has a plunger on it that moves back and forth slowly to adjust amount of air mixture, it is controlled by computer. Unplug it and just turn on key and check for voltage.This valve gets real gummed up, probably need to take apart throttle body and clean. HUNT

Jul 12, 2009 | 1987 Isuzu Trooper

1 Answer

Surges or bucks at steady speed, 40 to 50 mph


change fuel filter have injection system cleaned

Mar 11, 2009 | 1996 Chevrolet S-10 Pickup

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