Engine Stutter at 3500 rpm's

hargs79

Member
:
2003 Mazdaspeed Protege (Black Mica)
I've just recently started getting a "Stutter" when accelerating in gears 3 - 5 at around 3500 and 4000 rpm's. I start accelerating fine, but when I shift into a higher gear and push down on the gas a little bit more, and put a little more stress on the engine, I get a BUMP, and the car stops accelerating for a split second.
I don't think it's the clutch slipping because the stutter doesn't induce a rapid RPM surge. I've only really noticed it when the weather is super cold, so it might just have something to do with that.
For now, I'm going to replace the spark plugs and give 'er an oil change. I'll reply if this fixes it.
If anyone's run into this and has an answer other than "Take it to the idiots at the Mazda Shop," please let me know. I'm over my warranty (I'm at 61k miles) and I've stopped using the Mazda shop ever since they've consistantly mis-diagnosed every single problem I've brought it in for.
Thanks in advance.
 
Mods

Sorry forgot to mention...bone stock engine.
My fault...I knew fuel cut was coming as a reply.
Thanks though.
 
hargs79 said:
Sorry forgot to mention...bone stock engine.
My fault...I knew fuel cut was coming as a reply.
Thanks though.
hook up a o2 sensor to it... it could just be that ur engine is going lean. I know mine was that is why i went and got the AFC
 
I think it has something to do with the A/F mixture and the ECU. My N/A Pro5 did a little lastnight and the temps were in the 20's here. I new it wasn't a mechanical problem since it didn't do it everytime. I just reset the ECU so it might be that it is still re-learning my new setup.
 
Air/Fuel Mix

Yeah, everyone's probably right about the fuel cut or air/fuel mix. I'm going to try some fuel injector cleaner, some dry gas and the aforementioned stuff. It's definitely something that's triggered by cold weather because it ran fine during the day yesterday, but it happened again at night, and I've been able to get the car to do it pretty consistently when it happens. Thanks again for the suggestions.
 
how severe is the jerk? Is it like hitting a wall or does the car just not pull smoothly?
My car hates cold weather and you can feel the ecu just dumping random ammounts of fuel in the midrange RPM at partial throttle.
But thats all getting fixed soon.. very soon.
 
Engine Jerk

KyRaceFan said:
how severe is the jerk? Is it like hitting a wall or does the car just not pull smoothly?
My car hates cold weather and you can feel the ecu just dumping random ammounts of fuel in the midrange RPM at partial throttle.
But thats all getting fixed soon.. very soon.

I understated the jerk...it's not a stutter, it's more of a knock, the whole car jolts and it seems to happen pretty frequently between the range of 3200 and 4200 RPM's.
I thought it was just happening in extremely cold weather (under 15 degrees), but it seems to be happening in moderately cold weather (low 40's) also. I bought some gas anti-freeze and tried that, it didn't solve it, and I'm trying fuel injector cleaner right now on this tank of gas, also unsuccessfully.
I haven't really done any research on the matter, but how do you reset the ECU? Is it something that I can do myself?
I appreciate the help.
 
Rest ECU:
Disconnect neg bat terminal
Step on brake to get rid of power in system
let sit for 10 minutes
re-hook up your battery

your done
 
Won't you have to reset factory alarm after that??? When I reset my ECU my alarm went crazy. Wouldn't stop and even stopped me driving the car for a while. Something to think about unless you know a way not to upset the factory alarm.
 
did you just unplug the battery to reset the ecu? B/C that wont do it. You have to pump the brakes like 5 times, and then reconnect the battery.
 
daedalus said:
did you just unplug the battery to reset the ecu? B/C that wont do it. You have to pump the brakes like 5 times, and then reconnect the battery.

I didn't try the brake thing...but disconnecting the fuse to the ECU should do the same thing as disconnecting the battery, no?
I'm going to try pumping the brakes this time...thanks for the advice.
 
Well if its fuel cut, then you will need an FCD, and ive got one i will sell you. Its used, but its not a part you can really wear out. Breeze to install as well.

PM me if you are interested.
 
thank god someone else seems to have that problem. I am printing this thread and taking it to the dealer or else they will think that i am nuts. I've been having this problem for 2 weeks now. though i'm in florida, we've had mid 20s to 40s weather lately and the car just scared the crap out of me the first time it happened. It jerk violently in the early morning when cold, even on second gear, and it will do it again on 3rd through 5th if you are to try passing and depressing your gas pedal. When it gets hotter later in the day, the 2nd gear will run ok, but the rest of the gears will still cause the stumbling when you get on the gas to pass. As of last night, my CEL came on. I will have the car at the dealer this week and maybe the CEL will let us know what's going on. I will definitely let you all know if this gets solved. I'll keep you all updated.
 
Yeah, same thing

skrecht said:
thank god someone else seems to have that problem. I am printing this thread and taking it to the dealer or else they will think that i am nuts. I've been having this problem for 2 weeks now. though i'm in florida, we've had mid 20s to 40s weather lately and the car just scared the crap out of me the first time it happened. It jerk violently in the early morning when cold, even on second gear, and it will do it again on 3rd through 5th if you are to try passing and depressing your gas pedal. When it gets hotter later in the day, the 2nd gear will run ok, but the rest of the gears will still cause the stumbling when you get on the gas to pass. As of last night, my CEL came on. I will have the car at the dealer this week and maybe the CEL will let us know what's going on. I will definitely let you all know if this gets solved. I'll keep you all updated.
Yeah, definitely let me know if they find anything...my warranty has expired, and I don't trust the guys at my mazda shop anyway. Sounds like the exact same thing that's happening to mine. I tried resetting the ECU with the instructions posted earlier in this thread, but I think it only temporarily helped because after driving for 10 minutes, it started doing it again.
I'm definitely getting the Fuel Cut Defensor though.
 
Fuel Cut Defensor

I just asked a friend of mine about adding the fuel cut defensor, and he said not to without a EGT or A/F gauge because I might risk detonation because the car's dumping fuel in to decrease the temperature. Is this the case with our cars, or does it not apply because they already run rich?
 
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