losing power briefly?
 

hi guys and gals, i have a 05 tC with about 10k on it. during normal driving have any of you experienced a brief drop in engine power and rpms for a fraction of a second then everything is back running smoothly. the engine seems to hesitatea fraction of a second losing power with the tach needle dropping a little bit then all is fine. it has happened at freeway cruising speed and street driving too. this only happens occasionally and not all the time.

the engine is fully warmed up too. my tc is an automatic. this condition just started a few weeks ago. it has never done this before. any thoughts on what might be causing this?

I have no idea, but I would head to the dealer immediately. That does not sound good.

pick up the phone and call your dealer.

you could also check battery connections. I was doing 75 on the highway at night in my mr2 with the tops off, and I didn't get the battery connections on all the way, hit a bump, everything....EVERYTHING went black. Thank God for the moon. Very scary 10 seconds of getting to the shoulder and slowing down.

what kind of weather was it??

this happend to me in my MT xB on a snow trip, driving in the snow, up hill 5 ppl in the car, about 35 mph...

the headlights dimmed, interior lights dimmed and the motor seemed to do the "hesitation" that you mention...

i will definately check my battery connections

Re: losing power briefly?
 

I have the automatic transmission too, and the same thing happens to me.
BTW i have 7300 miles on my car

what the pause is, is the transmission deciding which gear it wants to go in, it will drop into neutral for a brief second, and then put you back into the highest gear possible. i believe they did this as a safety on the transmission which is supposed to increase its life span. I wouldn't worry. However, it is a little annoying lol.

Re: losing power briefly?
 

Yeah, I actually drive the 5 speed. When I shift quick, usually from 1 to to or 2 to 3, I can feel a slight blank than I can feel the power pull later.
As far as the tach dropping, cant really tell because shifting, driving and staring at the dash aren't a good mix.
I hope someone can elaborate, or maybe let us know that its normal, im proabbly going to take the previous posters word on calling up scion.

VVT-i kicking in is how I think of it, since its variable it only kicks in when needed correct? If your at that low RPM its not needed...

Somebody correct me??? Thats what I keep telling myself :P

VVT-i is always active, so you wouldnt feel anything kick in.

dont kno where u got this info from... did u make this up urself? completly wrong for those of u believing this... the variable valve timing changes the vlave speed when suddenly speeding up.... if i had to compare i would say V-tec only more advanced cuz of the computer... i say the transmision putting itself in neutral to find the best gear is the best answer!

i'm 98% sure its the tranny switching to neutral, thats why you feel your body moving forward when this happens, and feel normal again after it finds the gear it wants to be in.

Thanks for the correction...
My car does the same thing though, can anybody explain the real reason?

you have a manual?

i would assume its the flywheel thats causing your sudden loss of power.

could this problem be fuel related possibly caused by bad gasoline or a dirty fuel injector? maybe a sensor is going bad? map sensor? throttle positioning sensor? transmission beginning to go bad? since this problem only happens sometimes it will be hard to pinpoint at the dealer and the technician will probably come back saying cannot duplicate problem. the best thing to do is get it documented at the dealer until symptoms become worse. any additional thoughts? thanks guys.

if it was fuel related, it would always happen, not only when the car shifts. If a sensor was bad, then you would see a check engine light.

you know what i'm thinking is you have a hesitation in your engine, not enough to throw a check engine light.. you might want to find some BG Product's 44K fuel cleaner, dump it into an empty tank, fill it up.. and see what happens, i bet your problem goes away..

I had some slight hesitation in my tC.. within the first 10k miles.. dumped some of the 44K into the tank and never came back.. so if you're noticing a loss of power, it might've been a build up in the fuel injectors.. and that won't throw a code..

yeah it can happen in as little as a couple thousand miles.. now people here might tell you to get Chevron w/ Technron cleaner.. but naw, i've used it before doesn't work.. 44K is all that works.. it's what most mechanics use as well..

http://www.bgprod.com is where you can locate a shop that sells 44K.. i found mine at a chevrolet dealership :)

i had this power loss feeling in my tc once. (5-speed) it was just after getting gas so i attributed it to "bad gas". it hasn't happened since.

thanks for all the suggestions guys. sciontc_mich always has good answers. i respect your suggestion on getting some bg 44k cleaner thanks for the link.

sure no problem bts.. glad to help out..

yeah you gotta add this stuff like when you have a 1/4 tank or so, then fill up.. it helps mix it up in the tank when filling up..

one other thing to know about this stuff, get an oil change after this cleaner is done and you have gotten another tank of gas.. just safety really, it's how i've been doing it for a couple years and haven't had any problems by doing it this way. when this gets into the combustion chamber, it can get on the cylinder walls and it can mix a little with the oil.. just to be on the safe side.. just letting you know.. no worries :)

so let us know how it goes with the "missing" in the engine after using this.. :)

I am having the same problem under WOT usally in third gear sometimes in second, and turning hard.

It has nearly killed me three times. Nothing worse then losing power in a turn hard at a good speed in a front drive car.

I am clueless and the dealer is useless since they cant make it happen.

I am really upset because I love the car but I am getting ready to get rid of it because of this.

I think it has something to do with the drive by wire.

the car is a 5spd with 11,500 miles.

yeah, it's with the drive by wire.

there's a 0.5 second delay when you hit the gas. auto tranny + drive by wire... unresponsive car.