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Problem just started this morning... i should mention its been about an average of -10 to -15 degrees celcius in my area for the last week or so and it warmed up quick this morning to about 0. Not sure if outside temps are a factor but you never know.
anyway, this morning i hopped into the car (93 mx3 4 cyl SOHC, 5 spd), started her up and let her idle a little. Well the idle dropped way down... i'd say a hair away from stalling. it didnt stall though but i figure i should try to nip this problem in the bud. i drove it the 30 miles to work... no issues on the highway, but it felt like it would stall at traffic lights and stop signs when i got into the city... although it never did. when i got to work, i let it run in idle for a bit, and same thing... just a hair above stalling.
Car only has about 165000 km on it (or just over 100000 miles). i bought this past summer at about 150000 km. It's run great so far... it only burns a little oil, but not much. i have noticed lately that MPG's have been down a bit from what they were before.

i thought i would start with fresh plugs and new fuel filters (i read somewhere there are 2 in this car?)... already checked the air filter and its nearly spotless.

any other ideas?

I'm not sure the 4-cyl has an idle air control, but that would be my first guess, stuck or broken.

I'm not sure the 4-cyl has an idle air control, but that would be my first guess, stuck or broken.

It does have an IAC, and +1 to it being stuck or broken...

thanks for the help guys... i rechecked everything and there was a vaccum hose i missed. the one connected to the air tube. tightened it back up and she's purring like a kitten.

thanks again

I was going to suggest it was a vacuum leak, glad you figured it out

I have the same problem, but i can not find a vacuum leak. I have replace the battery (it was bad), i have also replaced the alternator. It is a stock 1993 4 cylinder

spray some carb cleaner around the areas where there are vacuum lines, the idle will raise when you find a leak as the the fluid will burn off when it gets sucked in.

mx3sohc wrote:spray some carb cleaner around the areas where there are vacuum lines, the idle will raise when you find a leak as the the fluid will burn off when it gets sucked in.

I did that still no leak. I am thinking it might be the IAC

It keeps failing the emissions idle test. the garage thinks it is the computer. What do you think? I have changed the O2 sensor, catalytic converter, I have cleaned the IAC, changed the plugs, and chaned the PCV valve. It reads 0.00 CO% at 2500 RPMs, and 37 HC ppm at 2500 RPMs, at idle it reads 2.81 for the CO % and 249 HC ppm. The idle is not stable.

next cheapish thing to replace is the temp sensor.