Sticky Throttle? Anti-stall?

[slam525i]

Okay, so I have one of those not-reproduceable problems, and I thought maybe someone here has seen it before.

Relevant Spec: 2010 MZ3, 2.5L, Manual, no mods

So, twice now, as I coast to a stop in 3rd gear, I clutch in at about 1000 RPM, foot off the gas, but the revs climb as if I'm at part-throttle until it reaches 3k (takes about 2 seconds), hangs there for about a second and then drops back down. It doesn't feel like the anti-stall kicking in as that usually happens when I clutch-in late (about 600 rpm), I can feel it through the car, and the revs only climb to about 1200 after I clutch in. Both times the symptoms are identical, my foot is clear of the gas, and I didn't clutch-in late as I coasted to a stop.

I'm thinking something's wrong with the anti-stall / idle logic, causing it to open the throttle, which then sticks either electronically or mechanically. I have an OBD2 transmitter but it doesn't log and I didn't catch it in-action (otherwise I could confirm the throttle position). It only happened twice in the last 200 km, and the car is perfectly normal after. I have no issues with throttle response or engine power otherwise.

I doubt this can be "diagnosed by internet", but I'm wondering if anyone has had anything similar.

(Incidentally, if this was an auto instead of a manual, the car would be in the shop; I wouldn't dare drive an auto with a potential electronic throttle problem.)

[Fuman]

@slam525i: This is the 2nd or 3rd post I saw regarding this problem. Are you okay if we rename this thread as per below?
@Mods, if slam525i is okay, can we rename this thread to: "Sudden Rev jump to 3K"?

I would like to document the number of members having this issue, and the circumstances in which this happens in one single thread. Once we have 3-4 people documented it, I think we can go to Mazda Canada and have them do an investigation. If they do not respond, we can contact the Ministry of Transportation.

slam525i or another member having this problem should take a lead on this issue and have Mazda come to a resolution.

edit: similar thread http://www.torontomazda3.ca/forum/showthread.php?61508-Engine-Rev-While-Braking&p=905661&highlight=rev#post905661

[DingosKidneys]

I have had this happen a few times, I don't remember the EXACT details of gear and speed, but it was strange enough for me to remember it happening :) clutch in and not applying gas. 2010 MZ3 2.5L manual, no performance mods

[Fuman]

Let's keep a tally of affected members
Affected members:
1. slam525i (2.5L Manual)
2. DingosKidneys (2.5L Manual)

[Kiyomi]

1. slam525i (2.5L Manual)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5l Manaul) <--but hasnt happend in over a year now.

[slam525i]

Interesting to know it's not just me. I have no issues about consolidating the threads. (I didn't see the other one. My bad.)

I would venture a guess to say this probably happens to automatics too, but isn't noticeable in automatics as the throttle is only slightly open, the brake easily over powers the engine, and the torque converter keeps the revs low. (I know the throttle is only part open because the revs aren't "jumping" up to 3k. It's much slower than a quick tap rev-matching tap on the gas.) The fact that all 3 of us have 2.5L may just be because people who prefer manuals also prefer the bigger engine.

The other interesting correlation is that the other thread was started 3 days ago; Maybe it's affected by the environment? Fuel quality? (I'm using Shell bronze.)

The first time it happened, my GF thought I had some how bungled up a heel-toe. The second time, we were both confused (in a parking lot, obviously not rev matching).

I'm shying away from bringing it to a dealer / Mazda / Transportation Safety Board as I cannot reproduce the problem and there are no codes being thrown. In other words, they'll think I'm nuts, I can't drive, or I have a sticking floor mat.

From the other thread:
Kiyomi, it can't be excess gas being burnt as our cars are fuel injected, ruling out a laggy rich carb being the problem. (I think...)

Slideways, I don't think it's a mechanical interference as it self-resolves. I don't need to tap the gas or anything to make it drop back down.

Harbour rat, I'm curious as my knowledge of car systems is limited, and airplane engines don't have vacuum systems. (Well, that's a lie. They have mechanical vacuum pumps because the manifold air pressure in airplanes are high.) How does the vacuum system affect the revs?

[Fuman]

I think if we have 4-5 ppl affected, we can ping Mazda Canada and see how they want to proceed with this hard to diagnose issue.

[TrueDon]

I have also experienced this issue...last time was today but she hit the brakes hard enough to stop from hitting the car in front. Took the car to Mazda and described the issue to Scarborough Mazda they pretty much said nothing we can do.
2008 Mazda 3 Sport GT. Auto.

[Fuman]

I have also experienced this issue...last time was today but she hit the brakes hard enough to stop from hitting the car in front. Took the car to Mazda and described the issue to Scarborough Mazda they pretty much said nothing we can do.
2008 Mazda 3 Sport GT. Auto.
did you notice what rev did it go up to?

New posters, please keep this tally up to date.

1. slam525i (2.5L Manual)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5l Manaul) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto)

[Hyperion]

1. slam525i (2.5L Manual)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5l Manaul) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto)
5. Hyperion (2.0L Manual)

[derekl]

1. slam525i (2.5L Manual)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5l Manaul) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto)
5. Hyperion (2.0L Manual)
6. Derekl (2.5L Manual)

[Hyperion]

We should add the year

1. slam525i (2.5L Manual)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5l Manaul, 2010) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto)
5. Hyperion (2.0L Manual, 2010)
6. Derekl (2.5L Manual)

[slam525i]

1. slam525i (2.5L Manual, 2010)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5L Manual, 2010) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto, 2008)
5. Hyperion (2.0L Manual, 2010)
6. Derekl (2.5L Manual)

[TrueDon]

did you notice what rev did it go up to?

My wife didn't notice the rpms...and I did not either when it happened before. Has anyone who has experienced this reported it to their dealership/service center? I kinda kicking myself for not reporting it earlier, it's good to have it on the record.

[Fuman]

Hey,

So I called Mazda of Canada, and they are now aware of this thread. However, I do not believe they are actively looking at this.
They suggested that affected members go to the dealer. I understand this is a hard to diagnose/reproduce issue so let's put a little bit more information below.

Format
0. Username(Engine size, drivetrain, year, dealer that you went to, frequency in which this happens, the rev that it goes up to)
1. slam525i (2.5L Manual, 2010)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5L Manual, 2010) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto, 2008)
5. Hyperion (2.0L Manual, 2010)
6. Derekl (2.5L Manual)

[Hyperion]

0. Username(Engine size, drivetrain, year, dealer that you went to, frequency in which this happens, the rev that it goes up to)
1. slam525i (2.5L Manual, 2010)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5L Manual, 2010) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto, 2008)
5. Hyperion (2.0L Manual, 2010, Avante, Completely Random, 3k)
6. Derekl (2.5L Manual)

[TrueDon]

0. Username(Engine size, drivetrain, year, dealer that you went to, frequency in which this happens, the rev that it goes up to)
1. slam525i (2.5L Manual, 2010)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5L Manual, 2010) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto, 2008, Scarborough, Random)
5. Hyperion (2.0L Manual, 2010, Avante, Completely Random, 3k)
6. Derekl (2.5L Manual)

When I mentioned this to my co-worker who use to have a Mazda 3 2.3L, he said he had a similar experience but assumed that it was his foot hitting the brake and gas, which is what I though the first time it happened. Just wondering how many other people have had a similar experience and dismissed it.

[slam525i]

0. Username(Engine size, drivetrain, year, dealer that you went to, frequency in which this happens, the rev that it goes up to)
1. slam525i (2.5L Manual, 2010, 2x last 200 km 0x for the last 3 years, ~3000 RPM slowly)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5L Manual, 2010) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto, 2008)
5. Hyperion (2.0L Manual, 2010, Avante, Completely Random, 3k)
6. Derekl (2.5L Manual)

[slam525i]

When I mentioned this to my co-worker who use to have a Mazda 3 2.3L, he said he had a similar experience but assumed that it was his foot hitting the brake and gas, which is what I though the first time it happened. Just wondering how many other people have had a similar experience and dismissed it.

I thought of that the first time it happened, but I've been heel-toeing this car with no problems for the last 3 years. The second time it happened, it was clearly not accidental throttle input as my right foot was completely clear.

[Bouncx5]

Ya this is happening to me and my car is 2 weeks old! at 1000rpm while braking it goes up. doesnt happen every brake
0. Username(Engine size, drivetrain, year, dealer that you went to, frequency in which this happens, the rev that it goes up to)
1. slam525i (2.5L Manual, 2010, 2x last 200 km 0x for the last 3 years, ~3000 RPM slowly)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5L Manual, 2010) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto, 2008)
5. Hyperion (2.0L Manual, 2010, Avante, Completely Random, 3k)
6. Derekl (2.5L Manual)
7. Brian 2.5l auto 2012

[goodcase]

Ya this is happening to me and my car is 2 weeks old! at 1000rpm while braking it goes up. doesnt happen every brake
0. Username(Engine size, drivetrain, year, dealer that you went to, frequency in which this happens, the rev that it goes up to)
1. slam525i (2.5L Manual, 2010, 2x last 200 km 0x for the last 3 years, ~3000 RPM slowly)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5L Manual, 2010) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto, 2008)
5. Hyperion (2.0L Manual, 2010, Avante, Completely Random, 3k)
6. Derekl (2.5L Manual)
7. Brian 2.5l auto 2012
8. goodcase (2.5L manual, burlington mazda, very erratic, ~3k)

I do find that if this is happening and i tap the gas it stops doing it.

[kilo4321]

Same thing happens to me, randomly... impossible to replicate on demand obviously lol

0. Username(Engine size, drivetrain, year, dealer that you went to, frequency in which this happens, the rev that it goes up to)
1. slam525i (2.5L Manual, 2010, 2x last 200 km 0x for the last 3 years, ~3000 RPM slowly)
2. DingosKidneys (2.5L Manual)
3. Kiyomi (2.5L Manual, 2010) <--but hasnt happend in over a year now.
4. TurDon (2.3L Auto, 2008)
5. Hyperion (2.0L Manual, 2010, Avante, Completely Random, 3k)
6. Derekl (2.5L Manual)
7. Brian (2.5l auto 2012)
8. goodcase (2.5L manual, burlington mazda, very erratic, ~3k)
9. Kilo4321 (2.0L Manual, 2011, Moffats Northwood, Completely random, 3k 'ish)