bak3rme

99 sr5 3.4l v6
260k miles on the Odm

changed spark plugs
cleaned TB
cleaned MAF
changed fuel filter
changed air filter
just did transmission fluid change.
rear diff. fluid change
oil/oil filter change
radiator fluid flush

all done within the past 4 or 5 months

i sometimes stumble across a rumbling/shaking from my car when im stoped at a red light or just parked for more than 10 or more seconds. Most people would let it go, because its not really of an issue. but it whenever it starts to rumble and shake..my rpm's drop really low (below 500) and it kinda splutters and tries to stay alive. Basically if i stop to long, about 80% of the time, ill get the rumbling and rpm's will drop and it will feel as if the car will shut down........which it has 3 times. However it rumbles alot, and only 3 times did it cut out. I usually have to give it some gas when im stopped to make sure it doesnt cut out

any thoughts?
thanks!

Edit*
Brian2sun, oops, forgot it idles at 500ish..sorry i meant it dipped below that almost to 0

brian2sun

You described really low rpms as being under 1000. A 3.4 idles at about 650-750 and when in "D" it drops to about 550-650. Obviously since it's stalling it's too low at times and there is a problem here, but your #s are kind of confusing since it should always be well below 1000 except for the first 5 minutes or so after a cold start up.

My first guess on the stalling would be a dirty IAC valve. Did you clean it too when you cleaned the TB (it's the green/grey plactic valve screwed to the bottom of the TB)? When you clean the TB but not the IAC, the crap from the TB can easily fall/run in the IAC and gunk it up, especially if you did not remove the TB off the truck to clean it.

how long has this been an issue, before you did that list of stuff or after? How old are your plug wires?

whokrz

Is your check engine light on? I would assume it would be running like that.
My 97 4runner acted like this and then threw miss fire on cyl#3. It turned out to be a fuel injector that went bad.
Also in my sig there is a link to factory service manuals.

BajaRunner

I second cleaning the IAC! Its a very common problem. It gets gummed up quite often and causes rough idle.

Its located/attached right underneath the butterfly valve/throttle body. Clean it!

Check it:
https://www.yotatech.com/forums/f123...ac-pics-92286/

bak3rme

sorry ur right i just couldnt remember if it was 1k or 500..its usually at 500 when parked at a light..then it starts to studder and get lower to like 100 or 200

bak3rme

thats interesting..been on here for a while and havn't seen that. i will give it a try. just take it apart and spray it down?

brian2sun

I would recommend getting a new gasket for the IAC and you might as well get the TB gasket too (both together were <$10 at the dealer). You'll need to use a little bit of RTV silicone (I used Permatex "The Right Stuff") on the mating surface to the TB also, but not too much as you don't want it to get sucked into the IAC. You can clean it with TB cleaner - just spray and wipe until the valve opens and closes freely. Be very careful removing the screws that hold it to the TB also, they are brass or something and really easy to strip out.

bak3rme

thanks, but what exactly do the gaskets do? for both , like to me..all the TB gasket is..is like a middle piece between 2 metals. also. i know there is an O shaped and a D shaped..would there be any harm in replacing the D with an O gasket? why in the first place did they not put the O gasket but instead put the D. i dont want to be replacing something, if it shouldnt be there in the first place.

thanks

pendrag

Why do you need to use silicone + the gasket on the IAC valve / TB surface? I didn't see any sealant there when I had it off this afternoon. Are you referring to where that green unit (Can't think of the name for it) attaches to the IAC housing?

brian2sun

Yeah, sorry it's been a while since I looked at/cleaned mine. I did mean where the green unit (solenoid) attaches to the IAC housing. Those 2 brass screws are the really easy to strip ones too. Here's some pics:
https://www.yotatech.com/forums/f123...ac-pics-92286/

fightman80

Something simple to check.......try looking at your Engine Coolant. I was having the exact same symptoms, and it turned out that I had a coolant leak in one of the rear lines that go to the rear heater! We checked the coolant level only to find it extremely low! We located the leak, patched it up, and put more coolant in it, and my problem was solved. I check the coolant regularly now, but it hasn't dropped down since, and the truck is running 100% now.

Just my 2 cents......

hross14

AND--test your Throttle Position Sensor (TPS)--it also causes these kinds of problems.