Car Idling Rough

[Sky_high]

Symptom: car idles rough when at a complete stop (i.e.- waiting at a traffic light). Once on the move, the engine runs perfect (accelerating and decelerating is fine). At idle, the rev's seem to be too low, (as if the engine skips a beat at times (I don't have a tach).

My car is a 1.6L and has 120,000 km on it. I have already changed:

-Timing belt 96,000
-Spark plugs at 100,000
-Spark plug wires at 100,000
-PCV valve at 96,00
-Oil changes every 5,000
-Cleaned the fuel injectors at 110,000 (using TerraClean System)

Note: there is no difference on the idle if accessories are on or off (i.e.- lights, radio (on low), wipers, fogs, etc...)

I can't figure out why it's idling rough? Seems to be progressively getting worse as the weeks go by. I am worried my alternator or battery may be the culprit (yes/no/maybe?)

Does anyone have any suggestions?

[5alive]

If it is just a minor rough idle, have you tried a different fuel vendor or grade? Just an idea... probably not a good one but hey...

[superdave]

Is the check engine light coming on at all?

[Sky_high]

Thanks for the replies,

Actually, I did move from 87 octane up to 89 octane. Problem is still there.

Check engine light has never come on.

[CarDemon]

YOu need a long highway trip of continous and sustained driving at highway speeds for over an 1hr 30min.

Let's go to ST. Jacobs Market one weekend and get farmer fresh pies. And of course we'll use your car buddy. http://msg.toprotege.com/iB_html/non-cgi/emoticons/biggrin.gif

[jali-p5]

is it idling rough when you have your angle-eye fogs on?? when did you first notice that it was idling rough?? after any mods??

[superdave]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Sky_high @ May 08 2003,06:32)</td></tr><tr><td id="QUOTE">Thanks for the replies,

Actually, I did move from 87 octane up to 89 octane. Problem is still there.

Check engine light has never come on.[/QUOTE]<span id='postcolor'>
Does the light work? IE when you have the car in the on position before starting it, does it come on? (just want to cover the basics http://msg.toprotege.com/iB_html/non-cgi/emoticons/wink.gif )

[Logan]

Sounds like it's time to get a Mazdaspeed.

[IceDragon]

Try cleanning your IAC (Idle Air Control) motor. A lot of times the motor will stick a bit, causing rough idle. Let me know if it works.

[7plymaple]

Maybe that Mass airflow sensor that you had changed under the recall? I remember you sayin that there was some trouble with it right after they changed it?

Dont worry have faith in the 1.6. http://msg.toprotege.com/iB_html/non-cgi/emoticons/wink.gif

[Sky_high]

Hey Guys, Thanks for the input!!

I don't believe it's accessories that's causing the problem.

Simon, I think you are right! It may be my new MAF sensor that I got, but now my car is out of warranty and basically I am screwed in that category!

BTW, What is a &quot;Idle Air Control&quot; and where is it located? I would like to check that system as well.

I was thinking that it may be my O2 (Oxygen) sensors! How many O2 sensors do we have in our cars? Does anyone know if they need to be replaced?

Well, I do hope I am able to resolve this problem soon.

[CarDemon]

To put an end to the guessing game, go to a reputable mechanic and more recommended, a Mazda Specialists. Get a Computerized Engine Diagonostic/Scope readout for around $79.00 and then you can go from there.

Or you can call up Miss Cleo or listen to everyone's hypothesis from here. http://msg.toprotege.com/iB_html/non-cgi/emoticons/wink.gif

&quot;I'd rather have x-rays, catscans, M.R.I's before thinking and letting a surgeon do exploratory surgery. Get my train of thought.&quot;

[Sky_high]

Well, I think I found out my problem on my little 1.6L.

Thanks to a friend of mine (from the Grand Am Club), he checked the sparkplug wires and he noticed white residue along one of the boots (far left cylinder to be exact). He told me that's not a good sign (carbon??). So we took out the sparkplug and low a behold, that spark plug was NOT in good shape (with only 20,000km on it). The other three sparkplugs are fine.

So we changed all sparkplugs and the wiring and she runs smoothly again (All original Mazda parts used). However, he said this is temporary fix- because there must be something causing in the one cylinder to wear out that one sparkplug quicker than the others. Hence, the rough idling!

Will keep you posted!

[Mike_Moss]

FYI: you can do the diagnostic check yourself...check your haynes manual.

[7plymaple]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Sky_high @ May 09 2003,11:18)</td></tr><tr><td id="QUOTE">Hey Guys, Thanks for the input!!

I don't believe it's accessories that's causing the problem.

Simon, I think you are right! It may be my new MAF sensor that I got, but now my car is out of warranty and basically I am screwed in that category!

BTW, What is a &quot;Idle Air Control&quot; and where is it located? I would like to check that system as well.

I was thinking that it may be my O2 (Oxygen) sensors! How many O2 sensors do we have in our cars? Does anyone know if they need to be replaced?

Well, I do hope I am able to resolve this problem soon.[/QUOTE]<span id='postcolor'>
Ya man I havent taken mine in for the recall on the mas because you told me yours did some weird stuff after they changed it.

If it aint broke dont fix it!!!!..... unless you think it would sound cooler. http://msg.toprotege.com/iB_html/non-cgi/emoticons/wink.gif

[CarDemon]

Computerized Engine Diagnotic to ease your mind!