YACT: hesitation/choke while accelerating from stop

[rh71]

2003 Mazda MPV... bought brand new several months ago and it's apparently been happening intermittently since then. Happens after a full 10-15 minute warmup as well. When casually accelerating from stop (lights/stop sign/whatever) it will jolt a bit for half a second... not sure to call it a hesitation or choke... but it feels like someone just hit you from behind... not really sure if it quits accelerating during that half second, but it's fine through all other gears and while decelerating.

I took a 25 minute trip with it once and it happened 3 different times after stops. You can't miss it if you're a passenger in the car.

Any ideas as to what the problem may be ? It's at the dealer (2nd time - 1st time was also for doing initial 3000 mile oil change) for this problem and they still claim they've never experienced it so far. I'm going to try and show them tomorrow morning. :|

 

[mandala]

I had a similar problem with a much older car. In that case the problem was the fuel filter (getting plugged up with crap that had gotten in the gas tank). However, I would be surprised if a new car had that problem (unless you got some really bad gas from somewhere).

 

[The Stigenator]

does it do it when the tank is half or quarter full?

I am wondering if the fuel pump is hiccuping or the fuel filter is clogged or somethign else.

 

[sillymofo]

Possibly torque converter? (auto right?)

 

[rh71]

yes - it's auto tranny... trying to find out about the fuel amounts when it typically happens... though I don't think that mattered.

 

[sillymofo]

Does it happens when you slowly accelerate as well? If it doesn't, then it's definitely the torque converter.

 

[The Stigenator]

reason being my mom's car (1997 dodge neon coupe) had a similar hiccup.. it would suddenly surge.. and suddenly choke and hesitate..

we changed tranny fluid, that didnt help much, finally a local mechanic (when it went for a smog test) found the problem.. apparenlty the fuel tank has a filter.. it was clogged..

it would do that only at lower tank levels, so my mom always kept the tank over 1/2 full.

the dodge dealer was useless in this case..

the car runs awesome now.

 

[ThisIsMatt]

Currently have a similar issue with my car...mechanic says it's an EGR (exhaust gas recirculator or something to that effect) problem...haven't decided if I want to fix it myself or not.

 

[The Stigenator]

well its a new car, the EGR cant clog so early... unless its a manufactguring defect.

 

[Quixfire]

I have been thinking about your problem and haven't come up with anything new to suggest. Sounds like a fuel or emission system failure causing the hesitation/choke concern.

Low fuel pressure or a lean run condition is the most common failure modes for your symptom.

Have you taken it to the dealership yet and if so what did they find out?

 

[rh71]

Well I got back around the time you last posted... the mechanic (who drove), his manager, and myself took it out of the service lot and the problem immediately revealed itself... happens on slower acceleration only (I guess I'm not usually hard on the gas). He says it's a "known issue" and is resolvable by a software update - something about the computer shifting it from 1st-2nd (though speed isn't even that high when this happens - is it really trying to shift into 2nd already??). WTF ?! - thanks for telling us about the potential issue in the first place.

Anyway, at least I finally got it out of them...

 

[Davegod75]

well i know with my 03 accord ex-v6 when i jam down the accelerator at any speed there is like a 1 sec delay before the car realizes i hit the pedal.

I've been told this normal but I don't quite believe it

 

[Davegod75]

sorry dp

 

[rh71]

Davegod, it's normal for a lot of cars, my '90 Accord has done that for many years and I've experienced it in my friend's 240sx. Maybe you want to give a fuel-injector cleaner a try... it may help a little if you're still unsure...

Anyway, I should mention about our problem that the dealer also said it's a "learning computer" that adapts to the way you drive (hence software update was involved)... and we need to give it 2 more weeks so it can re-adapt properly to avoid this choking motion... first time I've heard of this system... interesting.

 

[Davegod75]

car has done that since day one....i don't think it's a ditry fuel injector

 

[thomsbrain]

Originally posted by: Davegod75
well i know with my 03 accord ex-v6 when i jam down the accelerator at any speed there is like a 1 sec delay before the car realizes i hit the pedal.

I've been told this normal but I don't quite believe it

it's normal. happens with most autos. that's why sticks are good!