spray some brake cleaner or carb cleaner to clean the 2 wire coils in the MAF. very simple. takes you 1 minute. after you are done, the wire coils are shiny and clean. didn't really notice that much of a difference.

 

Hey guys
I am on my second 1st generation gs300 and I had a similar problem with both cars. I found out that the lexus grounding system is bad and which in turn throws the charge off when it comes to the battery. I cured my problem by installing a ground kit first and rebuilding my alternater. I found that the voltage stabalizer works great instead of sinking money into a new alternator it could be spendy. It worked for me maybe you guys want to give a chance. The only time my idle goes down is if my electrical fans comes on, not to mention my second gs is turbocharged. Hope this helps.......

 

Strange..My idle dropped from 600-700 to 200-300 just after I installed ground wire kit and voltage stabilizer

 

I've searched and could not tell where the wire coils are. Do you have to take apart the MAF? AllI can see is a plastic shape thing, but vented. Should I spray into the vent?

 

This is going to be a on going issue with the idle problem... My car does the same thing... A/C off 450rpm, A/C on 750rpm or so... IMO why would the PI TC be a issue with idle.. The TC should only affect rpm speeds when the car is in motion not at a stand still? Also if you have a drop in filter with oil on it it may get onto the MAF sensor and effect it that way who knows...

Has anyone came up with a conclusion to this? Even the lexus mechanics can't seem to get to the bottom of this as far as i know... People have replaced lots of parts and still have the same issue... Maybe its just the way these cars where built...

T

 

I had the accelarator assembly (throttle linkage) changed on my car due to a check engine light. After that fix, my idle actually improved . It used to idle at the 4th line in park before the fix. Now it idles 1 notch below 1k rpm in park. In drive it used to idle between the 2nd and 3rd line before the fix .Now it idles between the 3rd and 4th line which would be around 750-800 rpm. The car feels so much smoother now, cant tell if it is running

 

i have a 98 with the kn and a 2001 with the srt and the dragon,neither has a low idle problem, so i dont think that these are the cause of your problem, also i dont think its the ecu, ithink its a combination of maf,o2 sensors, and what ever else is telling the ecu whats going on that lets your idle drop so low

 

I have a 2003 GS430 and I have the low idle issue. I took the car to my dealership and they said "all GS4's do this". They did not make an attempt to fix it. Im going in for my 60k service and I am going to bring it up again.

 

2001 GS 430, does NOT have idle issues. Toyota's posted idle speed is 700-800rpm at operating temp. I have searched my toyota resources, and have come up with a few possible answers..

Low engine idle speed (Poor idling)
1. A/C signal circuit (Compressor circuit)
2. Fuel pump control circuit

Rough idling (Poor idling)
1. Compression
2. Fuel pump control circuit

Hunting (Poor idling)
1. ECM power source circuit
2. Fuel pump control circuit

 

This may be a dumb question, but have any of you guys tried adjusting your tps sensor? The reason I ask is because my car had a high idle so I took a chance and adjusted the tps counter clockwise and the idle went too low (like 4 or 500rpm). So I adjusted it clockwise with the engine running and got to idle at about 1100 rpm when engine is completely warm. That seams to be the sweet spot for me. In drive it now idles at 800 rpm. Drivability is a lot smoother. If any of you try this adjustment just beware it is a sensitive adjustment. I adjusted at about 1mm increments until I got it to asatisfactory
idle. It could probably be a litlle better but it is sooo much better than it was that I will leave well enough alone.

 

700-800 for a smooth v8 is pretty high imo

and who says that the stock in car tach is right? when doing emissions testing,i see tach variations from 100 to almost 450-500 rpms! (at 3500 rpm)

 

Okay.... Whatever works for you. I'm just stating my experience and what works for me. I know my car runs better now. Before, it idled at 1k rpm in drive, at operating temp. The idle was high enough to push against the stall on the torque converter. Now I dont have to stand on the brakes while sitting at the light and drivability overall is smoother. I dont think your statement was intentionally condescending but it kind of gave me the impression that you think Im an idiot. If I misinterpreted your statement or intent, I appologize.

 

Same problem! It was so bad that it would die on the street. My mechanic told me it happens a lot on Toyotas here in HK cause of the polution. Apparently there's a fast idle sensor that can get all gummed up. He took out my TB, cleaned it up and it was good as new.

 

yeah they do. it's just they way they are. go put yours in D when hot, with no lights or ac on and I'd bet it's idling at 500-600 tops. if your motor mounts are good, you'll hardly feel it. if they're tired, it's greatly magnified.

 

All these cars have low idle at times depending on many conditions.It is normal operation.I think some of the GS400's have ecu issues that cause the car to idle too low at times and die.I have all the above listed mods and my car did this when it was stock and still does.Not very often on a very hot day and after a hard run when I would come to a stop she would idle so low she would die.But if your car idles low and doesnt die I would think thats ideal.Less RPM=less gas use@idle.