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max kl · Post by **max kl** » November 3rd, 2006, 4:38 pm

i would rec. reading your plugs.
your description makes me think it an igniton missfire like from bad wires.
or realy lean mixture from a large vacume leak or torn vaf boot.

a lean mixture wil make a ignition miss worse. so i expect it to be both lean mixture & weak ignition.

Post by **Custommx3** » November 3rd, 2006, 5:33 pm

Stock ignition? If it doesnt need a tune up it could be distributor related.

Post by **Custommx3** » November 3rd, 2006, 5:34 pm

Stock ignition? If it doesnt need a tune up it could be distributor related.

BatMX3Man · Post by **BatMX3Man** » November 3rd, 2006, 6:33 pm

ariesdude · Post by **ariesdude** » November 4th, 2006, 2:01 am

Check your mounts first .....

panheader · Post by **panheader** » November 4th, 2006, 2:37 pm

I had that same thing happening, checked the plugs and they were shot. Replaced plugs and wires, runs like new.

Tempus · Post by **Tempus** » November 9th, 2006, 11:19 am

By studder do you mean a lurching or surging? like you are in a car with someone just learning to drive a stick?

Mine JUST started doing this, it's driving me nuts.. is worst in first gear, and it's a feedback loop kind of thing.. starts small and then gets worse and worse and worse.. rur rur rur rururu RUR RUR gets worse and worse, with steady pressure on the gas.. I can break out of it by accellerating hard (difficult in stop and go traffic), or putting in the clutch but that's it.. Almost impossible to drive it around at parking lot speeds..

Used to have no problems in stop and go.. could just stick it in gear, let it idle along, or give it a little gas.. Now it starts this surging lurching thing, more gas makes it worse unless I really put the pedal down (as in practicaly break the front wheels loose)

will check for intake leaks.. maybe try to pull and have a look at plugs when I get home.. Anything else could cause this? like a blown O2 sensor or something affecting the mixture?

Someone said check the mounts? I presume you mean motor mounts? why would they have an effect on this kind of behavior?

Tempus · Post by **Tempus** » November 9th, 2006, 4:39 pm

HAH Found it.

big crack on top of the joint between the thottle body and the MAF..

I'm sure this is flexing as the engine is loaded/unloaded, when it opens up, air through the MAF is reduced, and it leans out the mix, which looses power, then when the crack closes, MAF surges open, big dump of fuel to match the higher airflow..

also explains the 'feedback loop' behavior, as each lurch no doubt opened up the crack even further and that exagerated the effect..

At idle, with no load on the motor, the crack is no doubt much much more stable and consistent, and hence no lurching/surging effect when idling..

Now to find some duct tape to seal this up while I shop for and go get a new part..

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max kl · Post by **max kl** » November 9th, 2006, 11:32 pm

mazda still sells the boots and a company is remaking some dorman if you like i can get you a part#

but... this ia a perfect excuse to go get a cold air intake.
just tape the crap out of it and spend your money on cia parts!

jschrauwen · Post by **jschrauwen** » November 10th, 2006, 6:56 am

BatMX3Man wrote:My car studders going when I am driving if it is below 2000'ish rpms, like I have it in too high a gear, which I seriously doubt when it is in first leaving from a stop. And also it will not rev. up to the red line, stops at like 6500 rpm, like it used to. Not that I need those rpm's but just something I noticed when I got on it months ago. Mainly it is the studdering that is driving me nuts not sure what is wrong and hoping someone on here could help.
Thanks
Brian
PS It is a 92 GS 5spd if you need anyone that info. to help diagnose.

An old problem that has returned again along with a newer problem that is more of an annoyance. Perhaps because the first problem was never rectified correctly in the first place. The biggest problem that seems to be appearing these days are those from newer members who have semi recently picked up their MX which may be 2nd, 3rd or even 4th handed. Add to the mix that it's normally a younger person(s) as the previous owner(s) who may have been a little over exhuberant in their modding ideas.
So there's 2 distinct problems that may be related in some fashion. Problems that may have been created by previous owners and which may have been the catalyst of the sale to begine with. In order to make the best assist it's best that the OP state what mods are on the car, what has been done to try and fix said problems what didn't work, what appeared to make a small improvement. There is way too much vagueness in what's been given so far which would lead to random hypothizing.
BatMX3Man, you need to be more descriptive about the car's history including as much detail as possible. Having read previous threads as you should through a search you would have known that history and an in depth description of what has or has not been attempted to rectify the problem needs to be laid out. We are not master mechanics, we do not have crystal balls, but rely on the OP's story telling to best assist. Although at times it may be embarrassing for the OP to include everything, trust me when I say we've all made a few dandies and it's learning from those faupa's is where we move forward. So, fill in the gaps/blanks and it may be a much shorter process in getting to the root of the problem.

Tempus · Post by **Tempus** » November 10th, 2006, 5:58 pm

max kl wrote:mazda still sells the boots and a company is remaking some dorman if you like i can get you a part#

but... this ia a perfect excuse to go get a cold air intake.
just tape the crap out of it and spend your money on cia parts!

Well frankly, given the amount of flexing this thing has to take (it's not much, but it's frequent) I'd be worried about depending on tape, even good quality duct tape, holding it together in the long run.

BTW: little bit of duct tape made this thing INSTANTLY better and drivable again.. probably not a good long term fix but sure works till you can get the part replaced.

Now, if it was on the other side of the MAF sensor, or the airbox, yeah I'd probably just trash those parts and go for a CAI or at the very least a basic Cone filter setup. (I'll bet that airbox is NOT cheap)

I'd be partly tempted to just replace it with some rubber hose, as I believe someone here once did for a while, but for the fact that there's also a resonator tube that hangs off that thing (it's a Y not a pure accordian tube).. Given that the whole VRIS system is based on RESONANCE.. (the R in VRIS) doing anything that changes the characteristics of the intake system is bound to have an unknown effect on the resonance of the system..

The Mazda part number is K80113220D.. it's about $75 US.. it's labeled as an 'air pipe' in the repair manual. and fortunately University Mazda in Seattle (close to my work) has one in stock.

BTW this was in some ways a tricky one to find by searching here.. Just about everything I could find on 'surging' or 'lurching' all had to do with performance at idle.. Mine was idling just fine, it was at slow driving speeds, and mile acceleration that I had problems. This is perhaps because my tear was on the TOP of the part... if it had been elsewhere then the slight movement of the motor might have affected it differently.

Hopefully brian will have as easy a time resolving his 'studdering' problem as I did mine.

KanadianIceMan · Post by **KanadianIceMan** » February 16th, 2007, 7:18 pm

Well i didn't even know it but my car had duck tape on the manafold boot there already.

Took off the old, put on new tape, 1st i cleared it all really well, then put duck tape on ripped in half into the boot crack where it flexes, did 3 layers up on the sides got it all smooth and tight., then put 2 full around the whole boot.

I gotta say, its like a brand new car. Way more throttle response/control on the lower RMS, just off idle is like i have 20 more HP in there.

Highly reccomend doing small strips on the inside of where the boot flexes and get it tight on the sides. The negative pressure on the inside will make sure the tape is make a good connection. If the crack is all the way around get a new boot!

tehbrookzorz · Post by **tehbrookzorz** » February 17th, 2007, 1:02 am

Intake fabrication and other useful parts: http://www.vibrantperformance.com

That's what one of my local parts places suggested when I was trying to resolve my intermittent idle issues.

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Re: Engine/car studders below 2K.