MX-3.com

Hi,
I have a 1995 DOHC 1.6L i4 MX-3, and as of the last few months, I've noticed that my mileage has been pretty bad(around 350 KM to a tank) and that my idle was a bit rough. These symptoms, among the fact that when at operating temperature, my rpm would jump between 900-1350 RPM when in neutral, or stopped with the clutch in, led me to believe i needed to replace my MAF sensor. I found a junked car at the Pick-n-Pull in my city and got a MAF sensor + adaptor thingy that looked cleaner then mine. i proceeded to install it an have driven around forty KM with it and have not noticed any change with it at all, still got the poor mileage, and still got the jumping RPM along with the rough idle. I plan on getting some cleaner in the morning and cleaning the MAF sensor but the problem is, I don't know how to remove the sensor from the actual adaptor thing. to reference it looks like this (http://i.pgcdn.com/pi/6/24/86/62486131_50.jpg) Also, my oil is pretty dirty and my spark plugs are just about due for a change, could that possibly be causing a problem with my cars mileage? If so, would it be this drastic? I've also hear that a finished O2 sensor can cause poor mileage as well, does it sound like that is my problem?

Thanks in advance.

The most common issue that would cause a jumping idle is a vacuum leak. Check the intake hose between the airbox and throttle body first. Check the vacuum hoses, replace your PCV valve just cause it's cheap.

Use a little ether and listen for a change in idle, flex the hoses and listen carefully.

I suggest you SeaFoam your engine, it won't hurt and will clean up the top end of your engine.

Daninski wrote:I suggest you SeaFoam your engine, it won't hurt and will clean up the top end of your engine.

I'm gonna sea foam before my next oil change in spring, I'm actually looking forward to it.


I figured out most of my problem was because of my intake which I have now replaced.

If you are running a cold air intake and have not hooked up the vacuum line that went to the air box then chances are that's the problem. If you have checked that and still having issues i would do all of the above.

check spark plugs, wires, cap and rotor, PCV valve, and O2 sensor. If you are up their in mileage than all could be factoring into the high idle.

You can always pull the plugs and lightly clean them with 400 grit sand paper and re gap them to get you by for a wile, also do the same to your distributor cap and rotor. doing this can help narrow down the gremlin, and cost next to nothing.