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Old 06-04-2014, 07:55 PM   #1
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Default Low RPM stutter

Lets get this out of the way.

I've also tried a little google and m.net without any real solid feedback.

So on my completely stock 2001 Miata i've been having a bit of a stutter issue.
The stutter occurs between 1000-2000rpm under heavy to heavyish load / acceleration. It's almost always worse after it's warmed up.
As soon as it's 2000rpm + it pulls just as **** *** slow as a stock miata should without any issues. (though i do feel that my 94 stock was quicker than this 01, perhaps weight difference)
Car has 70k miles and the plugs were changed and gaped correctly, new fuel filter, new rear O2 sensor. Oil change, air filter, and other general maintenance.

It seems pretty simple but i'd like to know if anyone else has had issues similar on stock 01's before i go throwing money at it.

I'd like to think one or both of the coils have gone funny, but my logic and knowledge tells me that if a coil were to go bad it would just die. Maybe not? Coils are a bit to expensive for me to just replace without a little more input. I've heard everything from crank sensor to O2 sensor. The car throws no code either.
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Old 06-04-2014, 08:01 PM   #2
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A miss-fire should throw a CEL, actually a flashing CEL.
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Old 06-04-2014, 08:47 PM   #3
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What kind of power do you expect a stock miata to make at 1k rpms?
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Old 06-05-2014, 02:17 AM   #4
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just random thoughts:
maybe your vtcs solenoid is janky
maybe your crank position sensor is too far away from the wheel
maybe a bad/weak coil or both
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Old 06-05-2014, 06:55 AM   #5
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Did you try cleaning the TB and MAF?
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Old 06-05-2014, 07:02 AM   #6
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Those were my ideas as well.

Quote:
Originally Posted by Left0verCurry View Post
Did you try cleaning the TB and MAF?
Yup, i did this too.
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Old 06-05-2014, 10:14 AM   #7
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I just drove my car to work and was thinking of your "1k-2k rpm" claim.

How the heck do you even keep the car that low? lol
Just curious, cause my commute is all city, and usually 45-50mph, and I still can't get it to stay under 2k aside from a split second in 1st gear, even if I "lug" it.

just another random observation
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Old 06-05-2014, 05:20 PM   #8
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Eh, i kinda drive it like an old man. I'm used to having a torquey american car.

Normally it's just getting up to speed, or if i slow down in gear and don't downshift.

I'll see if i can get a little video of it. It's pretty apparent and embarrassing when leaving a light misfiring.
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Old 06-05-2014, 06:19 PM   #9
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plug wires
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Old 06-05-2014, 07:01 PM   #10
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except its got cops
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Old 06-05-2014, 07:23 PM   #11
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I've heard of the elusive stock cops, but I've never before inspected under the hood of a 2001+ for them.

Why do you always have to be right, 18? go be right somewhere else!
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Old 06-05-2014, 08:17 PM   #12
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Technically it has both
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Old 02-11-2015, 05:43 PM   #13
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Bump.

So this seems to be getting a little worse.

Same story, when it's cold in the morning it drives fine. Once i drive my 30 miles home and if i'm driving like an ***, high RPMs, really putting a heavy load on the engine it is the worst.

If i come to a light and do a nice low rpm start without over revving and doing a "jack rabbit" start it will sputter and missfire like crazy. What could get heatsoaked / hot that would cause this, BUT only within 1000-2000rpm? Could be the new O2 sensor i put in, not working properly? MAF? Coils? Maybe something with these crazy butterflys my car has on the intake?
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Old 02-11-2015, 06:38 PM   #14
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Have you checked the codes even if it doesn't show one or flash?
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Old 02-11-2015, 07:00 PM   #15
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No code, BUT i do have a stored code for O2 sensor, the one i changed.
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Old 02-12-2015, 08:15 PM   #16
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How did you go about cleaning the maf?

and an even better question...it's like 8 degrees and snowing, why are you even driving the miata right now?
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Old 02-12-2015, 08:16 PM   #17
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MAF cleaner spray stuff in a can...

I drive the NB all year round. Probably why i have stupid little issues like this, it's really not meant for 16 inches of snow.
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Old 02-12-2015, 08:29 PM   #18
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I tried backing mine out of the garage the other day to make room for a side job, and I got stuck in the driveway after I had already shoveled! It probably doesn't help that I have bf rivals though? You sir are a brave man.

Like someone above already mentioned, have you checked the air gap between the crank sensor and the reluctor wheel on the crank pulley?

I had an issue with my 99 a couple years back where the crank sensor wiring that plugs into the main harness had the insulation rubbed off of it by the little hold down clip that keeps it away from the belts. It left the wiring exposed and every time it rained or I ran over a puddle it would start acting up the way you're describing. I never got a code either because it was so random and I rarely drove in the rain to begin with.
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Old 02-12-2015, 08:33 PM   #19
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I haven't checked that yet. Seems to be weird that it's related to heavy driving, weather it's 100F out or 3F out.

I drive from allen park to monroe for work too. So it's not like i'm just going down the street. The day we had all that snow a week or two ago i had to back down 3 freeway entrance ramps because of other people being stuck... With enough wheelspin this car can get through just about anything.
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Old 02-12-2015, 08:45 PM   #20
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I have nothing constructive to add, but if you have a gopro I'd love to see video of fording 18" of snow in a Miata
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