Minor problem - car dies at high speeds!

[LA2019GT-S]

Here's the deal. I was on the expressway, going about 70, when I shifted into nuetral at the off-ramp. The rpms went down, down, down...to zero. This has happened a number of times in the last 2 weeks. Also, the RPMs dip really low when I'm sitting in traffic once in a while. Somethin ain't right. All I've done to it is yanked the butterfly and have the K&N in. It's been that way for about a year now, so I can't imagine that that is somehow causing the problem (yes, I plugged the vacuumm hose). Any ideas?
Of course, there's always the dealer, but I think I should probably get the butterfly valve back in before I go.
Appreciate the advice!
Josh

[BRAK]

WOA ... please take it to toyota and find out the prob ... i hope this a rare occasion because i dont want that to happen to me!

[LA2019GT-S]

Yeah, I'll post what I find out. I suspect dirty fuel filter(s) from a bad tank of gas or something. What I was hoping to find out here is if this could possibly be related to the butterfly valve. Again, I don't think it's likely, but if for some reason its absence is messing with the ECU, I don't want to the dealer to give me any problems...I still am mystified as to why this happens only at high speeds, though.

[jaycee]

hmmm after a high speed drive my rpms drop really low when i slow down and stop.... to about 600 but it never stalled... knock on wood!

[SlasherX]

wait a minute..youre driving and put it into neutral, your rpms drop and you have a problem with your car?

dude thats normal for neutral, your tranny isnt in gear...the engine should return to idle while you roll.

[BRAK]

i think he is sayin that in neutral it dies.... like when he is waiting for a red light to turn green... it just dies.
I forgot to say that i have heard of VERY rough ideling in automatics ... like when i had my 2001 GT auto before my gts 6spd .. the auto sometimes (i had butterfly removed) would idle soo bad ... my girlfriend would look at me and say .... um wtf is that .... i reved it up in neutral and it went away .... it would do it like once every month or 2 ... especially after i drove it hard like going 80 or 90 .. then braking hard. I do think that maybe the ecu was gettin some weird signals errr somethin and still thought it was in motion or something .
Dont forget to tell us what the problem/solution is.
ty
nick

[GTS LAID]

its possible that you have a dirty MAF sensor... that'll mess with your idle for sure... take it in to the dealer.

[z6joker9]

Mine has been doing that for a while now too. I've been checking up on it and it turns out i was misfiring and now i know i either have no compression in cylinder 1(hole) or it's sticking...

basically that is EXACTLY what mine has been doing, and it's gotten alot worse the last month

[pokgai]

is there a way to check if my MAFS is dirty? could i fix it myself?

sometimes im at idle, and the rpms around around 800, but once in a while it goes up to 1100 hten down to 700 then up and down and i can hear it revving thru my exhuast. but thats only once in a while. i have Injen CAI. only like 4500 miles with it, should i clean it? or maybe rotate the filter so the part facing the wheel is turned?

[CeliMatz]

Here is your solution hopefully: I went to the dealer with this problem and they told me to use a fuel injector cleaner on a full gas tank. It fixed the problem completely for me. You can pick them up at pretty much any gas station. Hope this helps.

[SlasherX]

sounds to me like a dirty MAF and or clogged vaccuum lines, not your fuel injectors.

go to a store and get something called "electronic cleaner" now take out your MAF and spray some on the filament in it, or whatever teh celica uses to meter the incoming air.. now make sure it dries out before you put it back into teh car. then resest your ECU by unplugging your negative battery terminal for 30 minutes or so..connect it back up and see if that helps.

if you had a bad fuel injector or injectors youd experience hesitation and stumbling upon acceleration, not the car just suddenly dying out.

if this doesnt solve your problem, im gonna guess its a vaccum line that needs to be adjusted or fixed..be 100% positive they are all plugged in and connected and all plugs and switches are connected as well too..

do you have any check engine lights?

edit: i can't spell....

also..

CHECK YOUR THROTTLE POSITION SENSOR (tps)
i know on the DSM's, this is a screw near your valve cover that controls things like this..they become screwy with time and may need an adjustment. check your manual for its location and testing procedure.

[LA2019GT-S]

Thanks for all of the tips. I'm taking it into the dealer on Saturday to get the oil changed in any case, so I'll see what they say. In the mean time, I'll try the fuel injector cleaner and cleaning the MAF, because it couldn't hurt...
Finally, for those of you that go to the dealer for oil changes - do you ever worry about them seeing your engine mods? Again, I have almost nothing compared to most, but I suspect the dealer wouldn't see it that way. Basically, I'm just lazy and I don't want to put the butterfly back in before I go! But if it puts my warranty at risk, I'll definitely do it.

[Edit] Oh, one other thing to clear up the confusion. The idle is screwy pretty much all of the time now. It wants to stall at when I'm at a stop, but right when it dips down, it shoots back up. However, when I'm on the highway at high speeds, and start breaking in nuetral, it dies altogether, and I have to restart the car. Not a really happy feeling...

[z6joker9]

yep...mine does that...

like i said i have no compression in cylinder 1... i think it has to do with that...

i changed the plugs, put that useless injector cleaner in my gas, cleaned my throttle body, check the spark plug coils, cleaned the mafs, did a voodo dance and nothing helped so far... if anything it happens more now...

[SlasherX]

hmm..idle surge eh? to take a page out of the 5.0 book, you may want to check your idle air bypass solenoid.

disconnect that battery and hunt it down(if the car has one, it should for exhaust gas recirculation)

If it has large amounts of carbon deposits in it you may need to clean it using regular carburetor cleaner. You will have to remove it to do this, DO NOT clean it while it is on the car! If you have checked to make sure that your EGR, IAB, and TPS are clean and properly set and still have a problem..go back to toyota.

as for them noticing mods..my dealer couldn't have cared less. its totally dependent on how "cool" your service manager and staff are.

[LA2019GT-S]

Well, I didn't get a chance to get it in to the dealer this weekend - they were having some sort of promotion or something and the line to the service desk stretched into the frickin' showroom! However, I DID throw the butterfly valve back in for shyts'n'giggles. Oddly enough, it seems to have done the trick (either that, or resetting the ECU). The MAF seemed to be clean, so I didn't mess with it. There was a good amount of crap in my K&N, so I took care of that too. I'm gonna run it for a while with the butterfly in to see if it acts up again (it does idle a lot smoother with it in, I've noticed). I'll still mention it to the dealer when I get it in there, and let you know what they say.
Thanks again for the tips.
Josh

[erok]

There seems to be a correlation between idle surging and hard braking. Anyone have a theory on how the braking system could affect the engine?

[LA2019GT-S]

Well, I said I'd let a few people know what happened. Oddly enough, replacing the butterfly valve and/or resetting the ECU seems to have done the trick. I can't figure out why, but the problem is gone. I asked the dealer about it, and he said it could be any of the things mentioned earlier in this thread. So.... unless the problem pops up again, that's that.
Thanks again for your help
Josh

[Willis5050]

Originally posted by LA2019GT-S
Well, I said I'd let a few people know what happened. Oddly enough, replacing the butterfly valve and/or resetting the ECU seems to have done the trick. I can't figure out why, but the problem is gone. I asked the dealer about it, and he said it could be any of the things mentioned earlier in this thread. So.... unless the problem pops up again, that's that.
Thanks again for your help
Josh

Glad it's back to normal. I would keep an eye on it though, my idle problems come and go on a weekly basis. It also depeneds on what kind of driving I am doing. I am fine on the highway, but around town I get all sorts of problems. It seems like replacing the ECU and injectors is Toyota's cure all for idle problems - don't worry, I've done that TSB enough for everyone here, so you all should be fine.

[RedNOSceli]

Originally posted by erok
There seems to be a correlation between idle surging and hard braking. Anyone have a theory on how the braking system could affect the engine?

Hard Breaking will cause the engine vacume to come down sence the break booster runs off engine vacume. IE giving it the effect of a vacume leak. I figured they would have fixed this issue with newer cars. When I had an F-Body, the break booster went out and it would suck so much vacume, it would kill the engine.

[uansari]

Originally posted by SlasherX
wait a minute..youre driving and put it into neutral, your rpms drop and you have a problem with your car?

dude thats normal for neutral, your tranny isnt in gear...the engine should return to idle while you roll.

Why don't people read the whole thread?? :angry: j/k

Usman

[PeeWeeGTS]

Why would you ask that 4 months after he posted it?!

[ArchangelX]

Cuz he's :gay:

Duh. :thumbup: