My idle on my GS4 seems way low. It sits at about two notches above 0 - which I guess is about 400. I reset my ECU today and it didn't help. Sometimes it seems as if my car is going to stall.

What are you guy's idleing at? The car is a 99 with about 34K miles on it. Thanks for the help!

 

First thing to do is do make sure the RPM reading is accurate.
If it is reading correctly, have the TPS checked as this is a very common area on the GS.

 

I have had this problem too, seems to be just below the normal RPM at idle and is rough, right? Car NEVER died and I just got used to it (never got around to checking the TPS).

Couple of other items to try:

1) A recent post talked about cleaning the throttle body from buildup. Might want to try that.

2) Haven't noticed the rough idle since I put the Torquemaster spark plugs in. Only a day's driving thus far, but the rough idle was pretty regular and would have occured in normal driving.

 

Dave, is it possible it wasn't due to the TM plugs specifically, but that your old plugs were just fouled or worn to some extent?

 

Mileage is a bit low for carbon buildup to be an issue. Though not impossible.
I agree with Bit, if replacing plugs cured the problem then the original plugs were at fault. Any new plug woulld of fixed the issue.

 

Don't think so guys - I actually replaced the original plugs about 15K ago with OEM Denso's because I thought that might be the problem with the idle (and because I don't like the idea of 80K plugs).

I had the techs save the old ones for me to inspect, and they have some carbon buildup, but nothing fouled or worn about them. I used to do a LOT of plug changes back in the day with my old GTO engine w/ high compression (every 4k or so) and have plenty of experience with bad plugs. These looked OK.

 

i have my GS4 at the dealer right now for this problem. they said they could not find any problems with my car, and they say they can't duplicate the rough idling. they went ahead and cleaned my throttle body cuz they say it has carbon build up. but when i went to pick up my car, i was like, WTF, it's still idling rough. and i had one of the service guys sit in the car with me, and he was like, WTF. so i mentioned about the TPS to them and they said if I want them to check it, they're gonna charge my as$. they're gonna have their master technician have a run at my car this time and see what he says. if he thinks that the tps needs to be checked, they're gonna give me a call to give them the okay for repair. damn, i hate that rough idle.

 

That's crap; you should be allowed a free diagnosis; shoot, for a rought idle, the TPS should be one of the items they'd check anyway; why should they charge just for the TPS inspection?

Anyway, keep us posted.

 

Yeah, well I plan to take my GS to my dealer and see what they do to fix it. I just purchased the car about a month ago, so they better not pull any crap and ask me to pay anything. The idle is way low and the car feels like it is going to stall. I just ordered the TM's today, I wonder if that will help?

 

when you guys say "rough idle," do you mean the idle fluctuates and causes the car to shake. my idle sits at about 500 rpm in D and 700 in N, P, or when A/C is on. i have actually had the car turn off on me once, but it was after a quick race, so i figure it was just a coincidence. by the way, how much are these TM spark plugs?

 

i got my car back from the dealer yesterday. they said THEY COULD NOT FIND ANYTHING WRONG WITH MY CAR. they said that all 98-2000 models idle like this. i tried arguing TPS, but they say that it's "normal" for the GS4 to idle like this. they say that the GS4 and the LX470 idle a bit rough. what they did was clean out my throttle body for free cuz there was some carbon deposits build up. well, this morning, i noticed that when i started my car, my rpm was a bit higher than before, so i'm assuming that my car is breathing more freely than before. but still, i do have a low idle, but the car seems to be more quiet now. still some vibration, but i have to drive it a bit more to see what happens. also, if you never knew, turning on the AC is not the only way to bring up the rpm. turning on your headlights will do the same thing, so if you don't want to freeze your as$ when it's cold to stop the vibration, just turn on your lights. this draws more current and causes the engine to rev higher.

 

well my car idles low, but it doesnt vibrate or run roughly at idle. if it is at 500 rpm at idle and it is rough with vibration, then thats not normal. i idle at 500 with no problem, try another dealer. some dealers may not care enough to look into your problem.