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Ok, I have a 93 mx3 with b6 sohc, 5spd, & 197,xxx miles. I was driving it back from my kid's school today when it started acting up (right in front of the house, luckily). I slowed down to make the turn onto our side street , and the engine almost died. I tried to give it some gas, but it didn't make a difference. You could hear the change in the sound, though, like when you hear the intake sucking air. Anyway, it hung between about 200-600 rpm no matter how much I "fluttered" the gas. It actually did stall a couple times, but started right back up. When I got it into the driveway and shut it off, I thought, "I wonder if it's smoking when it's doing that?", so I hop back in, start it back up, and it runs just fine! WTF!!! I tried to make it do it again later, but it's running fine! I'm thinking fuel pump or filter, but I've read on here that these things have a tendency to lose their distributors, too. Does anybody have any suggestions for me on this one? This is my daily driver, and I'm gonna need it monday morning for work. It might make it, but I'm not sure I can trust it. Sorry for the long post, just wanted to make it as detailed as I could. Any help is truly appreciated.

Did it rain? Could have gotten water in the plugs. How long since last tune up? Clean air filter/fuel filter/plugs/wires/disty cap and rotor?

everything's clean and dry, it didn't rain until after this started. as far as the tune up, who knows? just bought the car maybe a month and a half ago. I know it could use wires, haven't checked the plugs, air filter's ok, cap and rotor are ok, but not great. I washed the engine once and got the distributor all wet inside (a month ago, not today), but then it was at least firing 2 cylinders pretty consistently. this seemed like everything was cutting out, either all fuel or all spark. can't really check it though, because it's not acting up anymore.

sounds like a torn intake boot, start checking for cracks.

so I have noticed just a small hiccup in accelleration, but only sometimes, and only just from idle. I'm still thinking it's a fuel pump, but I'm not positive, and I don't want to change it if it's not the problem. is there a way to check the distributor so I'm not just throwing parts at it? I don't know if it's related, it probably is, but I have noticed a "surging" under accelleration ever since I got the car.

nos92mx3 wrote:sounds like a torn intake boot, start checking for cracks.

+1 I had a phantom problem with my gs for awhile until a nice tech at the hyundai dealer found a small tear from the intake. Every time the engine pulled at the mounts it twisted enough to make a gap in the intake you wouldnt see otherwise

Sleeper6 wrote:

nos92mx3 wrote:sounds like a torn intake boot, start checking for cracks.

+1 I had a phantom problem with my gs for awhile until a nice tech at the hyundai dealer found a small tear from the intake. Every time the engine pulled at the mounts it twisted enough to make a gap in the intake you wouldnt see otherwise

that doesn't make a lot of sense to me, it just doesn't seem like it could be that simple. however, I did pull the intake hose off - the one from the filter box to the engine - (that's the one you're thinking of, right?) and inspected it. it has a few small cracks that don't look to me like they go completely through the rubber, they remind me of the cracks you would see on an aging tire. tomorrow I will try pulling and wiggling the hose with the engine running, and I will also spray some carb cleaner in the area of the cracks to see if anything happens.

myfirstmazda wrote:

Sleeper6 wrote:

nos92mx3 wrote:sounds like a torn intake boot, start checking for cracks.

+1 I had a phantom problem with my gs for awhile until a nice tech at the hyundai dealer found a small tear from the intake. Every time the engine pulled at the mounts it twisted enough to make a gap in the intake you wouldnt see otherwise

that doesn't make a lot of sense to me, it just doesn't seem like it could be that simple. however, I did pull the intake hose off - the one from the filter box to the engine - (that's the one you're thinking of, right?) and inspected it. it has a few small cracks that don't look to me like they go completely through the rubber, they remind me of the cracks you would see on an aging tire. tomorrow I will try pulling and wiggling the hose with the engine running, and I will also spray some carb cleaner in the area of the cracks to see if anything happens.

You better believe it could be that simple... When air gets drawn into the engine through cracks in the intake boot, it bypasses the MAF/VAF, resulting in unaccounted for air, and throwing off the stoichiometric air/fuel ratio.

This == car runs like crap whenever the torque of the engine causes the tear to open up further.

VERY common issue on these cars...

Hope everything works out for ya

Edit** If your vacuum leak test turns out okay, then you may be looking at distributor failure or temperature sensor failure. The problem seems like it could be temperature dependent, since when you shut the car off and restarted it some time later, it ran fine.

To be honest though, if you know the car needs a tune-up (you have no idea when it was last done), we shouldn't even be talking about all these things. Grab some new spark plugs and wires (if needed), change you fuel filter, throw in a new distributor cap & rotor, and then report back with the status.

spray the boot and the lines coming off the boot (valve cover and IACM).
spray the fuel injector oring areas, throttle body and gasket area.

Duct tape/electrical tape can be used for quick fix/diag.
Your correct on your fuel pump idea, but you also must know inside of our VAF's there is a switch that turns the fuel pump on/off. So if you have a vaccuum leak after the VAF, it could be tripping that switch.

The torn boot is an abusurdly common issue with these cars.
Start there.

ok, sprayed every part of that boot, even opened up the cracks as much as possible and sprayed right into them, no change in idle at alll. I'm running out of time to figure this out, so I'm just gonna keep driving it until the problem makes itself more obvious. also, I didn't say I restarted it some time later, it was probably not even a minute later. that rules out your temp sensor idea, so this brings it back to the question, "how can I check the distributor?" I'm still leaning towards the fuel pump, though. there is another issue that may or may not be related: if you let the car idle for more than a minute before shutting it off, it will smoke (white) like a pig when you start it cold, BUT IT'S NOT OIL, it's unburned fuel. I thought maybe there was an injector leaking into the engine all night, so I pulled the injectors to look at them, they didn't have great big globs of crap stuck to them, so I put them back in. I messed up 2 of the o-rings, so I put new o-rings on and CAREFULLY re-assembled it. smoked like hell again this morning. I don't know, I'm just going to drive it until whatever it is finally goes out.

myfirstmazda wrote:...also, I didn't say I restarted it some time later, it was probably not even a minute later. that rules out your temp sensor idea, so this brings it back to the question, "how can I check the distributor?"...

Sorry to ruin your day... your welcome for making an effort to try and help you regardless..

Also, you said you washed your engine. Every time I do that, water pools up in the spark plug wells, causing the spark to short directly to the block, bypassing the spark plugs. Engine misfires horribly and hardly runs when this happens. I grab the compressed air, pull the spark plug wires, and blow the water out of the wells. Runs like a top after that.

Happens EVERY time I wash the engine...

another issue with these cars is grounding.
There should be a main ground for the fuel injectors by the thermostat housing, i know when mine was loose the car would act up like your describing, also over by the battery tray.
Also check the ground at the fuel pump, take off the bottom seat cover, take off the metal plate undo the connection and theres your sending unit, your lucky if it is the fuel pump they are very easy to do.

just ran out and checked the grounds under the hood real quick... couldn't find any loose.
everybody's help is really appreciated, and I think I'm just going to end up driving it until the problem becomes obvious. I'll keep ya posted, may only be a few days... if you come up with anything else to check, let me know. till then, PEACE!

where are you from?