Scion iM Forum banner

Sudden deceleration!!

4504 Views 13 Replies 7 Participants Last post by  runnermedic
A few days ago i noticed that when cruising on gears over 3rd sometimes a deceleration hiccup happens just for a second,long trips short trips no codes no warning lights.mines is a 6 speed no mods.
anyone noticed same issue???
1 - 14 of 14 Posts
Never happened to me, do you know if the AC is on when it happens?
Are you equipped with Collision Avoidance? Someone had mentioned that it will automatically decelerate the engine. If you have it and it's turned on maybe it's glitching.
Ac on or off is the same,next week is the 1st schedule check up im going to ask the tech.
Happened to me yesterday. Two stop lights in a row. From a dead stop starting moving, then no acceleration; coasting for 2-3 seconds. Very dangerous. Pulled into a parking lot and couldn't replicate.
Gas warning light was on, don't think it was too low to be running out of fuel. Drove for 10 miles trying to duplicate problem, and never could. Filled up with gas at the end of outing. Started and stopped the engine three times. Weather here in TX was extremely hot at the time. Temp on car read 100 degrees. Only happened at the beginning of the drive after first startup. Lunchtime at 12 after arriving at work at 8:30.
I was in traffic and panicked about being hit; didn't notice if the check engine light flashed at all. CEL wasn't on after the incidents at all. Has never come on or stayed on that I've seen. Car only has 2000 miles on it.
Going to buy a code reader and see if there's anything there. If it happens again or the CEL comes on it's going to the dealer. I should probably take to to the dealer anyway. Hmmm.
I suspect this is a DBW issue; and I hit "limp mode" for a second.

I hate the idea of DBW.

Only thing I've done to the car is add a K&N drop in air filter. Same one I see mentioned here in other posts.

2017 Toyota CVT
See less See more
if you both have toyota's then it might be collision detection, no beeping or lights at all? did it feel like the car was braking or just coasting all of a sudden?
most common when cruising and you press the pedal just a bit to gain speed thats how i noticed! took mine to service and they found nothing! they looked 1st at the gas pedal connection then moved to the tb then wiring then codes scanner and to end test a 10 min drive and no issues! but yes its a dbw thing for sure.
Didn't feel like the car was braking. Nope. Didn't seem like collision detection. The cars ahead of me had long increased the gap when the lights went green. And no, no beeping no flashing alarm on the center screen. Felt like the car was in neutral but the rpms didn't shoot up at all, just didn't respond for those moments, when it did it was a bit sluggish, then all of a sudden fine. If it happens when I'm trying to move out into fast traffic, like getting on a feeder road from a parking lot, where everyone is speeding trying to get on the freeway. Well, yikes. Freaking vote of no confidence. Hasn't happened since. Knock on wood.

Haven't experienced runner medic's phenomenon though. I use cruise a lot, and frequently step on the pedal to increase speed and then turn it off. Never have had a problem in that situation.

What I've read about collision detection so far is that it will auto brake if no action is taken after the alarm has been set off. And I've read elsewhere that some cars automatically decrease throttle when the brake is pressed as a safety feature. Didn't feel like there was braking or drag.
See less See more
Didn't feel like the car was braking. Nope. Didn't seem like collision detection. The cars ahead of me had long increased the gap when the lights went green. And no, no beeping no flashing alarm on the center screen. Felt like the car was in neutral but the rpms didn't shoot up at all, just didn't respond for those moments, when it did it was a bit sluggish, then all of a sudden fine. If it happens when I'm trying to move out into fast traffic, like getting on a feeder road from a parking lot, where everyone is speeding trying to get on the freeway. Well, yikes. Freaking vote of no confidence. Hasn't happened since. Knock on wood.

Haven't experienced runner medic's phenomenon though. I use cruise a lot, and frequently step on the pedal to increase speed and then turn it off. Never have had a problem in that situation.

What I've read about collision detection so far is that it will auto brake if no action is taken after the alarm has been set off. And I've read elsewhere that some cars automatically decrease throttle when the brake is pressed as a safety feature. Didn't feel like there was braking or drag.
I am not an expert on VSC but I think it has got something to do with it. I found the description on the owners manual. It may be experiencing some hiccups. Here is the description below:

Attachments

See less See more
Interesting, thoughts on VSC.

It's been awhile since this incident and everything has been good so far (knock on wood).

When using CC on the highway I experience no hiccup when applying more accelerator to increase speed; what I do notice is that it takes a moment for the rpms to climb to close to 4000 (from 2000; which is where ECO has them sitting when cruising). Once it gets closer to 4000 then I start to feel power and acceleration. This is normal lag I think, since max torque is at 4000 and it's only 126ft/lbs or so.

I got a code reader, so I'll repost with anything that I find out.
Well, I got a code reader and the car is completely clear. No codes at all. No recurrence of incident. knock on wood again.
I'm beginning to think the electronics "crashed" or had a bad "boot up". At first service I'll inquire if there are any software updates.

Loving the car though.
Well, I got a code reader and the car is completely clear. No codes at all. No recurrence of incident. knock on wood again.
I'm beginning to think the electronics "crashed" or had a bad "boot up". At first service I'll inquire if there are any software updates.

Loving the car though.
Good to know
in my case happened with out the use of cc,just simple a to b short trips and i noticed that it also happens when car is downhill and you slightly press the gas at the end of that hill to gain speed just a split second but noticable,maybe the issue is on the gas pedal switch
1 - 14 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top