Bouncing RPM's

[Hustlin1]

So i spent 2 hours trying to search this problem but everytime i thought i found similar symptoms, i found some inconsistencies. Anyway, here is whats happening: for the most part the car runs fine, but every now and then, maybe every 50 miles or so when i stop at a traffic light the rpm's start "bouncing" and the car acts as if it wants to stall out. It might do this for 2 quick lights then stops and the problem does not come back for another 50 or so miles. The car has not stalled yet but the rpm's bounce dramatically, approx 800 to 400. It has yet to trip a code yet, not even a misfire. Occasionally when i start moving again the car hesitates for a few seconds but then gets up and goes normally. Sometimes revving it will stop the problem, sometimes it won't. The plugs are in good shape, the wires and vacuum lines are all fine. The throttle body is clean. The car is running on 92 octane, tried injector cleaner. Basically, i am asking if there is a sensor or something that could cause such problems yet still not trip a code. Any help would be greatly appreciated cuz with this sort of problem we all know what a mechanic or esp a dealership will do/charge me just to not fix a damn thing. BTW it is a 1999 Solara SE V6 Auto

[krawzyazn]

Idle control sensor or clean the throttle body

[Hustlin1]

Anyway to test to see if the ICS is working properly?

[Turbosolara]

mileage?

[Hustlin1]

76,xxx

[lilm]

if your were lookin at post u prolly saw mine.....mine just kinda dissapeared i would clean replace all the vaccum lines and clean the tb


if that doesnt work smack the engine with a wrench

[Hustlin1]

yeah, i def read your post on this, the difference being from what you said and others in your post and what my car is doing is the rpm's change dramatically and the car has not shut off yet which leads me to believe a sensor or something along those lines is going out but without a code telling me what is not happy i am a little lost. so is there a way to test the ICS or the TPS etc. to see what they are doing

[DaTwUnKrAziEpInOy]

maybe a vacuum hose...

[lilm]

how many miles you got?

[Smoothro]

I had a similar problem with my '99 V6 SLE. However, my RPMS would fluctuate even while I was driving, it was barely noticable, but there was a little stutter. It did throw a CEL that eventually went off after a while. I beleive my problem was caused by bad gas, possibly some with a little water in it or something, because shortly after I filled up again the problem went away. I did have to end up replacing the O2 sensor and PCV valve, so not sure if either of those contributed or not. So that was my experience...

[Hustlin1]

When my car starts doing this a a light or stop sign, for the first few seconds after i take off it feels like it wants to fall on its face but after mashing the gas it stops and won't do anything wrong for a while there after. The throttle body is clean, the pcv is clean, plugs and wires are good, all vacuum lines that i can trck are fine, and still no code. i am about to take lilm111's advice and hit it with a wrench! if a sensor was going out, it should throw a code, if the cat was clogged the O2 sensor should pick it up and it shold throw a code so i am at my whits end. i hate the thought of guessing and starting to replace things and not solve the problem been down that road before and its too expensive.

[Mole]

So i spent 2 hours trying to search this problem but everytime i thought i found similar symptoms, i found some inconsistencies. Anyway, here is whats happening: for the most part the car runs fine, but every now and then, maybe every 50 miles or so when i stop at a traffic light the rpm's start "bouncing" and the car acts as if it wants to stall out. It might do this for 2 quick lights then stops and the problem does not come back for another 50 or so miles. The car has not stalled yet but the rpm's bounce dramatically, approx 800 to 400. It has yet to trip a code yet, not even a misfire. Occasionally when i start moving again the car hesitates for a few seconds but then gets up and goes normally. Sometimes revving it will stop the problem, sometimes it won't. The plugs are in good shape, the wires and vacuum lines are all fine. The throttle body is clean. The car is running on 92 octane, tried injector cleaner. Basically, i am asking if there is a sensor or something that could cause such problems yet still not trip a code. Any help would be greatly appreciated cuz with this sort of problem we all know what a mechanic or esp a dealership will do/charge me just to not fix a damn thing. BTW it is a 1999 Solara SE V6 Auto

are you stock?

how often does this replicate?

Can you tell when this happens or is about to happen?

[Hustlin1]

The car is 100% stock, it happens at completely random times. car will be running fine and then i stop at a light or a stop sign and it just startsfalling on its face, it has never stalled out completely but sure feels like it wants to.....after i get started again the car hesitates for a about 2000 rpms then takes off as usual sometimes it gets in cycles when it will do it for a few stop signs in a row then after it gets over it, it won't happen again for a day or so.......any new ideas???

[Too Bzy]

The car is 100% stock.......any new ideas???

I know you're stock but with the short air intake when you disconnect the battery and do your first start it up my car does that until the computer "learns" again that the open filter is there. Just in case I guess I'd check to make sure the intake houses are tight and there aren't any leaks.

[Mole]

I'm willing to bet there's a nik in the fuel delivery.

Check the
fuel filter
fuel pump
injectors