slight lunge releasing acc pedal?

[canadave]

Sort of an odd thing I just noticed. The last few times I've driven my 04 Vibe, there've been a few times (not all the time) when it felt like the car lunged forward slightly (just barely noticeable) when taking my foot off the accelerator. Most times it's been on straight level roads at low speeds (50-60km/hr), where I wasn't pressing much on the accelerator to begin with. Has anyone else noticed this?

[KITT222]

If you are accelerating quickly, then let off so you stop accelerating and start going a constant speed the automatic in these cars can buck, or 'hiccup' as I like to say, when it shifts from the lower gear to higher gear. It's really pronounced if you're on the accelerator, revving to 4000+ rpms, then pull your foot completely off the gas pedal when you reach 50/60mph. It's a characteristic of this transmission. It's known for hard shifts, and acting a little wonky.

[lannvouivre]

Did you ever do the PCM recall? Maybe it didn't affect your year...Mine's an '06 and was very "special" when it had the bad PCM (which ended up dying spectacularly and being replaced under warranty before the recall)

[canadave]

Thanks for the replies. Yep, did the PCM recall (and all other recalls).

As for the acceleration...no, this isn't the "bucking" you're referring to (although I know exactly the bucking you're talking about..I've experienced that several times too). This is different. I drive and accelerate slowly and smoothly...in this case, I'm talking about driving at constant low speed (50-60 *KM*/hr, not mph) with my foot slightly on the gas, then taking my foot off (such as when approaching a slight downhill grade). When I take my foot off in cases like this, I'm occasionally feeling a slight "jump" forward, as if the car is lunging slightly. Not dramatic or anything--just barely enough to be noticeable. And it doesn't seem to be all the time, nor is it 100% able to be replicated on command.

[KITT222]

Maybe try cleaning the throttle body and cruise control thing under the hood. Maybe try lubricating the throttle cable as well.

[canadave]

Those are two very good ideas. Will try that and report back at some point (won't be able to get to it for a while). Quick question--how would I go about cleaning the throttle cable? Not even sure where that is, and Google isn't being as friendly to me as it usually is

[KITT222]

The throttle cable is the cable running from the pedal to the throttle body. 03/04 Vibes have a physical metal cable running to the throttle. Just open the hood, look for the throttle body, then you'll see the rotor (half-moon thing) with a cable going into some black sheething. Use a lubricant, and spray it into the sheething until it comes out the other end, and jiggle it a little. If you have cruise control you will have two cables to check: from pedal to cruise control module (located to the DS of the engine, near the firewall, has black cover and two cables going into it), then CC module to throttle.

[Caretaker]

yes, I have the same problem, even though I have the 2009 Vibe. I have 76,000 miles on the car and have had new WS tranny fluid put in last year. I have never had any engine work done. Over the past year, I have noticed fluctuating RPMs from 1000 to 1400 or so. It seems more pronounced when the air conditioning system is on, but does seem to occur after I let off the accelerator, most noticeably (obviously from the RPM numbers above) at low speeds. I had my mechanic perform a full throttle body cleaning in case this was a simple matter of carbon build up. While slightly improved, after 1 month, it does not seem to have rectified the problem. So my lunging is more of the RPMs dancing back and forth within a 400 rev area. I am curious to see what others say about this. Probably perfectly normal for a stupid 4 speed automatic tranny; now woefully outdated in today's car market.

[lannvouivre]

Probably perfectly normal for a stupid 4 speed automatic tranny; now woefully outdated in today's car market.

Yeah, mine does that. I love how smooth the shifts tend to be. 1-2 is a bit rough when you back off the gas and it decides to upshift anyway, and some of the other things it does are aggravating when you're not expecting them (like shifting on hills). Otherwise, it blows my mom's '08 Mercury Mariner right out of the water. That thing shifts like it's trying to get revenge on you.