Still having problems with the rough idle. I have to brake very slowly because if I brake hard, then it will start to idle violently and it may stall on me again. Also, a few times when I go to rev the engine before shutting it off, I felt like the engine shook a little bit. This tells me the engine mounts are bad. Could it be the engine mounts, or both engine mounts and my spark plugs/coils/wires?

So today my car stalled out while I was at a stop light for the first time since I bought the car.

Recently, my car has been idleing roughly every now and then when I come to a stop light.

It usually shakes roughly, but then goes back above 750 RPM's and doesn't stall. But today, it started shaking roughly and then everything stopped and 4 or 5 lights came on, including CEL, Battery Light, and a few others.

Could this be because of Engine Mounts? I had a thread a few days ago asking about rough idleing, and a few people have told me that it could be my Engine Mounts.

Could that be the source of why my car stalled out, or would it be because of something else?

Well bad motor mounts would not cause your car to stall, but they will cause the car to idle rough. I would check. your igniton coils, spark plugs and spark plug wires. Also check your battery for corrosion and to see if the terminals are tight. How many miles are on your coils and spark plugs now?

^^^ very good advice.
how many miles on the car?
original battery?
how old are coils, wires, plugs?
oh, and check your maf sensor / connections

my car stalled on my yesterday too an I have an A/T I was in shift mode Going about 90 an came to a quick stop to pay a toll went to hit the gas and NOTHING I put it in park and it started right up. although I'm not 100% sure Y it stalled on me Imo I think the rpms dropped way to fast it could be my spark plugs/wires or coils the battery is new I have 71600 mile on it I've had it for a year next month. anyone have another idea?

^^^ very good advice.
how many miles on the car?
original battery?
how old are coils, wires, plugs?
oh, and check your maf sensor / connections

34,800 miles on my car.
I am not sure if it is the original battery or not, but it is the same battery since I bought the car a few months ago.
The car has yet to have it's 37,500 mile service, so OLD Coils, Wires, and Plugs.
...stupid question...what is MAF sensor/connections?

I just want to make sure that it is probably the coils, wires, and plugs before I go and change them.

MAF Sensor - Mass Air Flow Sensor

If you look at your intake, there is a little connector right near the middle of it in your engine bay...that's the MAF. Check to make sure it is plugged in nice and tight, and you could even take the intake off and spray some MAF cleaner on it to make sure it's nice and clean.

The other advice here with plugs/wires/plugs are very good, and should be your first choice.

MAF Sensor - Mass Air Flow Sensor

If you look at your intake, there is a little connector right near the middle of it in your engine bay...that's the MAF. Check to make sure it is plugged in nice and tight, and you could even take the intake off and spray some MAF cleaner on it to make sure it's nice and clean.

The other advice here with plugs/wires/plugs are very good, and should be your first choice.

How much does new Plugs/Wires/Coils cost?

coils about 35 a piece
plugs 20 a piece
and wires around 90-110
depends on brand

How much does new Plugs/Wires/Coils cost?

Most people are getting the three for 250-300 dollars and you and a buddy can put them in, in about and hour. Most dealers want 600-700$.

Try SeaFoam you engine first. If it fix your problem then it $10 vs. $300.

Well today I found out that if I brake hard, then my car will idle rough too, but it never stalled out.

Could that be because of the same problem as when it stalled out?

Bump...still having problems!!!

your Throttle body/MAF is not functioning correctly.

or

engine could be bad.

Have you done any of the suggestions yet?

your Throttle body/MAF is not functioning correctly.

or

engine could be bad.

How would I go about fixing my Throttle Body/MAF?

This is how you check the sensor:


MAF Sensor - Mass Air Flow Sensor

If you look at your intake, there is a little connector right near the middle of it in your engine bay...that's the MAF. Check to make sure it is plugged in nice and tight, and you could even take the intake off and spray some MAF cleaner on it to make sure it's nice and clean.

The other advice here with plugs/wires/plugs are very good, and should be your first choice.


If it is dirty, then clean it. If it is bad, then replace it. You can pull out your MAF sensor to get a look at how dirty it is. If you are not sure how, then search in the DIY section for MAF sensor

For all of you who have this problem, whether A/T or M/T, please do the following:

1) Check your air filter. It needs to be clean.

2) Check your Mass-Airflow sensor. It should be clean. Also make sure the o-ring is in good shape and put some spit on it before you re-install the MAF sensor in the intake duct. To clean the sensor I use a Q-Tip and some rubbing alcohol.

3) Make sure your E-shaft sensor is also free from debris. This sensor is located directly under the A/C compressor and all you need to do is wipe any dust from the side closest to the trigger wheel.

4) Make sure all of your intake ducting is properly clamped and that the plastic elbows are not cracked/brittle. Also make sure all of your vacuum hoses are properly connected.

5) As also has been stated, the throttle body may need cleaning. To do this, remove the rubber intake ducting and spray some carb cleaner on a rag and wipe the interior radius of the throttle body while manually opening the butterfly. Make sure the car is "off" when you do this.

If none of this works we can move to the ignition system diagnoses.

This is how you check the sensor:





If it is dirty, then clean it. If it is bad, then replace it. You can pull out your MAF sensor to get a look at how dirty it is. If you are not sure how, then search in the DIY section for MAF sensor

I just pulled my MAF out today and its pretty clean ... but Im still using Stock Air Filter maybe thats why ?

This is how you check the sensor:





If it is dirty, then clean it. If it is bad, then replace it. You can pull out your MAF sensor to get a look at how dirty it is. If you are not sure how, then search in the DIY section for MAF sensor

How would the MAF sensor be making my car idle roughly and/or stalling out?

^This should answer your question

A MAF (Mass Air Flow) sensor measures air flow by sensing the effect of the heat transfer rate from a wire (usually platinum) placed in the air flow. The wire has a know temperature coefficient of resistance. In one of several possible implementations, a constant current is passed through the wire. This heats the wire up, and its resistance changes with the rise in temperature. Because the current is constant, the voltage drop across the wire is a direct measure of its resistance, and hence the temperature of the wire. The higher the air flow, the higher the heat transfer from the wire, hence the lower its temperature. Therefore the voltage across the wire decreases as the air flow increases (mass flow actually, because the heat transfer coefficient is dependent on both air density and velocity). There is a correlation between mass air flow and sensor temperature (voltage). The voltage is small.


I could not have said it better myself

quoted from:

http://www.rx8club.com/showthread.php?t=94872&page=2



In simpler terms:

quoted from wiki,

"A mass air flow sensor is used to find out the mass of air entering a fuel-injected engine. The air mass information is necessary for the engine control unit (ECU) to balance and deliver the correct fuel mass to the engine. Air changes its density as it expands and contracts with temperature and pressure. In automotive applications, air density varies with the ambient temperature and altitude, and this is an ideal application for a mass sensor. (See stoichiometry and ideal gas law.)

There are two common types of mass airflow sensors in usage on gasoline engines. These are the vane meter and the hot wire. Neither design employs technology that measures air mass directly. However, with an additional sensor or two, the engine's air mass flow rate can be accurately determined.

Both approaches are used almost exclusively on electronic fuel injection (EFI) engines. Both sensor designs output a 0 - 5.0 volt or a PWM signal that is proportional to the air mass flow rate, and both sensors have an intake air temperature (IAT) sensor incorporated into their housings.

When a MAF is used in conjunction with an oxygen sensor, the engine's air/fuel ratio can be controlled very accurately. The MAF sensor provides the open-loop predicted air flow information (the measured air flow) to the ECU, and the oxygen sensor provides closed-loop feedback in order to make minor corrections to the predicted air mass. Also see MAP sensor."

I am still not really understanding it to be honest.

I do not mean to sound dumb if I am....

I am still not really understanding it to be honest.

I do not mean to sound dumb if I am....

it simply means, MAF is used to "measure" the amount of air coming into the engine, it also measures the incoming air temperature. so the computer(ECU) will be like "Ahh, ok, X amount of air will be in @ this temperature, I should put Y amount of fuel to balance the mixture."

so if the MAF sensor is dirty, the Computer will NOT be able to know the "correct" amount of air coming in, and often the computer will "think" that it has "less air than it is" coming in. messing up all the mixture, so your engine idles funny.

I wont get into "open/closed" loop thing cuz it will confuse you more. but this is the basic meaning of "what MAF sensor is for"

it simply means, MAF is used to "measure" the amount of air coming into the engine, it also measures the incoming air temperature. so the computer(ECU) will be like "Ahh, ok, X amount of air will be in @ this temperature, I should put Y amount of fuel to balance the mixture."

so if the MAF sensor is dirty, the Computer will NOT be able to know the "correct" amount of air coming in, and often the computer will "think" that it has "less air than it is" coming in. messing up all the mixture, so your engine idles funny.

I wont get into "open/closed" loop thing cuz it will confuse you more. but this is the basic meaning of "what MAF sensor is for"

No you explained it perfectly, I understand it now. Thanks.

Is there a DIY on here to show someone how to clean their MAF?

Is there a DIY on here to show someone how to clean their MAF?

http://www.rx8club.com/showpost.php?p=2927771&postcount=9

Thanks!

Nice DIY, as always, Jon. Now all you need is an oil catch can and breather filter. ;)

There are also specific MAF cleaner sprays at the 'zone and the like.

The ECU output is only as good as the sensor input, in this case most likely the need for a cleaner MAF and/or air filter. Damn computer age. ;)

Now all you need is an oil catch can and breather filter. ;)
LOL... true!
I know it'll bite me in the ass one day if I keep putting it off.

There are also specific MAF cleaner sprays at the 'zone and the like.
True.
An electronic contact cleaner will work the same on your MAF as a "MAF cleaner", but if you feel more comfortable using the bottle that says its for the MAF then use that.
I don't think the price difference is much (if at all).

LOL... true!
I know it'll bite me in the ass one day if I keep putting it off.


True.
An electronic contact cleaner will work the same on your MAF as a "MAF cleaner", but if you feel more comfortable using the bottle that says its for the MAF then use that.
I don't think the price difference is much (if at all).

There is a difference.

same bottle size, Electonic cleaner cost like 5 bux. While MAF cleaner cost 7 bux. :rollingla

Autozone :):rollingla:cussing:

So I was re-reading the DIY, and I have one quick question:

When you say remove the wire harness, does it just simply unplug from the MAF housing?

When you say remove the wire harness, does it just simply unplug from the MAF housing?

Yes.
You'll see a push-tab in the center of the harness.
Simply push that down with your thumb and pull the harness out.

What kind of MAF Cleaner do you use?

Personally... I've been using LPS's electro contact cleaner because I always have a supply around.
147580

But the MAF cleaner at the local Autozone will be fine.

Alright thanks for the help! I'll put the results up here once I am able to do work on it.

Yep, me too. 'been using it on electronics for years. I was just sayin'.....

Personally... I've been using LPS's electro contact cleaner because I always have a supply around.
147580

But the MAF cleaner at the local Autozone will be fine.

So I finally was able to buy some MAF Cleaner and work on my MAF Sensor today. I also cleaned my K&N Intake Filter while I was waiting.

However, once I reattached them both and turned my car on to see if it worked, my CEL is now on. Should I be worried?