What is the idle speed for everyone when the car is warm (after running 5-10km)? I seem to be getting unstable idle speed everytime I start the car 10-20 mins after driven for a couple kms... (e.g. drive from home to shopping mall -> start the car and leave the mall -> unstable idle speed at startup)

What could possibly cause this?

There's also an unreasonable amount of "shake" everytime I press / release the gas pedal... Guess it's time to take the car to dealer

 

to answer your question...it should be about 750 rpm.....

 

isn't it 700? says right under the hood

 

According to what it says under the hood, 700 rpm. When I start mine cold it idles high (anywhere from 1700 to 2200 rpm). I think this was a problem with the ECU/PCM (cold weather start rattle). Mazda has since provided an updated code to the dealer and I have had mine reprogrammed. But it has made no noticeable improvement. After the engine is warm the idle speed drops to around 700 rpms.

 

ru crazy?

When the engine is cold, It WILL idle anywhere from 1500 to 2500 rpm. if you sit with the car in P (or N) for about 5 minutes, u will notice that it will drop as the temp of the engine goes up and finally stabilize at 750rpm(in N) and if u put it in D, it will come down to 650-700rpm.

 

can u describe it better?

1. after u start the car , if u let it sit in N, what does the tach say?

2. in addition if u switch on the headlights, does it change? how much?

 

it would move a little bit, but still be around 400-500 range.

 

so what is erratic about it?

it is a diff. issue that the speed should be ~750rpm, and not 500 rpm.

what happens if you turn on the A/C ?

 

the issue is that after the engine is warmed up and I stop the car for 15-20 mins then start the car again, the car would be hard to start sometimes and the taco needle would drop to almost close to 0 before going back up to 400-500. After that the needle would still go up and down abit (~200-500) and the engine feels like almost dying...

this doesn't happen on cold starts

and another issue is that my car is shaking everytime I press/release the gas pendal. if I step on the gas real hard and fast, the car would appear hopping!!

 

Thanks for sorting me out there chikoo. But it seems to take a long time for my rpms to drop even when starting from 20-30 degree temperatures. Also, I noticed on my sister's civic and my brother's sentra and my fiance's mustang that their tachs drop within a minute or so of starting their cars, even in the cold.

 

The protege is quite different than other cars out there. LEarnt that after similar comparisons.

Hey, 3 reasons for that

1. Did u or anyone ever mess with the idle speed setting?
2. Faulty MAF
3. Leaky intake manifold gasket

I say this, 'cause I went thru this.