[JPeterman]

The ICE in my 2004 Prius doesn’t seem to run all that well. I have a stoplight near my house that is almost always red. When I go out in the morning and wait at this stoplight I can feel the ICE hiccup several times before it eventually shuts off. AC and heater are off. This may be a problem when warm but I don’t know since the ICE tends to shut down before I come to a complete stop on all but the first few miles of driving. The hiccups feel like a milder version of the bump you feel when the ICE shuts down. They are not regular and eventually a hiccup seems to lead to ICE shutdown. Does anyone have any comments on this issue before I bring the car into the shop.

 

[DanMan32]

Sounds normal. We all feel that shudder on ICE shutdown, as if it was running out of gas. A Toyota explained its cause during a forum, but a member here that attended couldn't get it down fast enough to relay to us. I suspect there is still fuel vapor in the intake manifold and in charcoal adsorber in air filter cover, so ECM allows spark but no additional fuel which burns it all up instead of letting it escape to the air.

If you have passengers, you can tell them you ran out of gas. I have actually done that. My best friend's daughter almost got fooled.

 

[JPeterman]

I'm not talking about the ICE shutdown shutter (although it's nice to hear it's normal). This is similar but slightly less severe shutter that takes place while the ICE is running and long before it shuts down. When the car is first turned on in the morning and I'm at a stop and the ICE is still running I feel a somewhat randomly timed shutter the entire time until finally the ICE shuts down (with a larger shutter that you mentioned). My assumption is that the ICE should run smoothly irrelevant of the temperature and this is not the case with my car.

 

[SkipHuffman]

I'm not talking about the ICE shutdown shutter (although it's nice to hear it's normal). This is similar but slightly less severe shutter that takes place while the ICE is running and long before it shuts down. When the car is first turned on in the morning and I'm at a stop and the ICE is still running I feel a somewhat randomly timed shutter the entire time until finally the ICE shuts down (with a larger shutter that you mentioned). My assumption is that the ICE should run smoothly irrelevant of the temperature and this is not the case with my car.

Could that be pinging? Have you switch gasoline's recently?

 

[JPeterman]

I don't think so. It's been there since I bought the car (almost a year ago). I usually hear pinging on acceleration and I don't hear that at all. It's more of a misfire. But it could also be the computer trying to turn the car off unsuccessfully.

 

[DanMan32]

Iv'e seen it 'skip a beat' when it is considering shutting down too.

 

[ken1784]

But it could also be the computer trying to turn the car off unsuccessfully.

Are you familiar with the Five Stages of warming up process?
Are you familiar with what's happening from Stage-3 to Stage-4?
http://priuschat.com/forums/kb.php?mode=article&k=14

Regards,
[email protected]

 

[Sanny]

Are you familiar with the Five Stages of warming up process?

The first stage is denial. Next comes anger or resentment. The third stage is bargaining. The fourth stage is depression. Finally comes acceptance.


Many of these can be avoided by a heavy sweater and wool socks.

 

[adamandgwen]

I had a hiccup last night for the first time, I have 3,000 miles on the ODO. Car should have been sufficiently warmed up, had been driving approximately 5 - 10 minutes when I came to a stop light. ICE tried to shut down, as soon as it did would kick back on, for a sequence of about 5 times until the light turned and I started cruising again. Hiccup is a very accurate way to describe. Didn't happen again.

 

[janitorjay]

I also experience this from time to time. It does seem to be an issue with the car trying to decide whether or not to turn the ICE off. It normally happens to me first thing in the morning when I come to a stop with the heat on. It was a little unnerving at first, but it doesn't seem to have any negative impact.

 

[Phoenix]

Just a comment...

The last two entries sound like "dieseling" from an over-rich mixture. This used to happen with low octane gas; but this was mainly with carburetor systems, not fuel injection.

 

[ken1784]

The hiccup is a kind of a ceremony called "idling check process".

The engine ECU is looking for the best idling rpm, then the vehicle moves from Stage-3 to Stage-4.

Regards,
[email protected]