i have a 1990 3.0 5speed 4runner and when its warm it idles really low. about 300-500. shakes a little when its that low. the thing is for the most part it only seems to do this at night. i thought maybe it would do it when its warm duting the day but i can drive it around for a long time during the day and it will be fine. but it seems that at night its really low like that. its never died. feels like its going too but it never has. everything else is fine. still drives the same. in the morning its good. most of the day its fine but at night its low. no matter how much i drive it during the day it will idle low and choppy at night

any ideas?
thanks

 

Sounds like your engine is being pulled down by the extra current required for the lights. This could be a problem with your alternator, or you may have a partial electrical short in something you are using at night. Try turning the lights on after it warms up in the daytime and see if the problem occurs.

 

huh... i never even thought about that. ill try that out.

 

How long since you cleaned the throttle body? There may be some gunk in the small idle passages that need cleaning. Be SURE to use cleaner specifically for throttle bodies (not 'carb' cleaner ).

Mike in Ar

 

me personally have never cleaned the TB. ive been thinking about it. ive owned the truck for 3 months so i dont know if it was ever cleaned before. how hard is it to clean?

 

quick update. i cleaned the TB today with some TB cleaner and she seems to be running good now. drove around. let it idle and so far its stayed right about 700-800. so far so good.

thanks for the help

 

ok i wish i could have let this thread die, but no. cleaning the TB didnt work. it did make it run smoother when it gets down to 500rpms. but its still idling low after driving it for a while. so i dont know what else to do. what else can it be that would cause my truck to idle low after driving it for a while

 

If you find out let me know. Mine does the same thing, except time of the day doesn't make any difference. Just when driven for a while the idle drops to around 5-600 rpm.

 

the idle contacts in the tps could be corroded. the hotter it gets the more resistance it builds due to the corrosion. or the efi temp sensor could be going bad also. this is only a couple of things that could cause the prob.

 

I have the same problem kind of. I just took off my cat and redid my intake setup and it idled at like 1400 so I turned the idle screw all the way in and it idles fine at around 700 but when it warms up it idle at around 200. If you figure anything out let me know.

 

Turn the idlescrew only when its warmed up

 

turn on your fan inside...i realize this is only fixes the simptums and not the problem. but no matter what anybody does, everything is a temp fix. i took my 91 Runner to a Toyota Specialist, he tried this and that, that and this and so on. Nothing works, it is just a Toyota thing i guess. so i always have my fan on low and it idles around 700-1000rpms.

 

turn your fan on low inside. this is a tamp fix, but it will always idle at proper speed then, no matter what. i have the exact same problem, mine idles low and sounds like it will die soon. I spent over $500cdn to try and fix this. i took it to a Toyota specialist. Nothing anybody does will fix it. It must be a Toyota thing is my guess.