I got a 2003 mazda protege 2.0 the check engin light came on. it drives great but when left to idle it sounds like its going to stall.

Lean Bank1 can be attributed to a faulty oxygen sensor or by unmetered air entering the system. A comon problem with the protege is cracks in the plastic air intake hose after the MAF which sucks air in that is not registed by the car and thus make it run lean and idle poorly
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Another comon problem causing rough idle is the EGR valve being stuck because of carbon deposits, this will usually throw an EGR related check engine light but not always.

Hi, it's just left of the battery when you are facing the front of the car.

What about new spark plugs and wires?

For a proper diagnosis and repair you first need to scan your engine control module to find out why it turned on the Check Engine light.

Solution 1 would be to diagnose the problem of the low comp in 2& 3 and solve that issue. I would of started w the timing belt 1st. If that didn't solve it,ck head gasket, valves,rings. CK for oil & coolant mixing. Good Luck

It sounds like the MAP (manifold absolute pressure) switch might be bad. Since the check engine light is on, have the computer codes read.

my 2001 mazda protege starts hard, idles low and high at various times (never normal) and it acts as though its going to stall at all times. sparks and wires are changed no help, changed air filter no help. any idea on what to do?

Take the car to a local Auto Parts Retailer, and have them check the fault codes on your on-board computer. Given the year of your car, it is probably an OBD-2 type computer. They can print out whatever the computer diagnostic says the problem is. I am going to guess the throttle position sensor is to blame since it sounds just like what my sister's Mazda Mommyvan was doing.

The idle on my 2003 Mazda Protege started acting strange one day - it kinda surged forward a little bit. Then the RPM would drop and kept wanting to stall out. It stalled out at a stop sign. The check engine light came on. I drove it immediately to my Goodyear mechanic. It ended up being the Idle Air Control Valve. They had to order the part from Mazda which took 3 days to get there. The whole thing cost $700. Runs great now (again).

I bet it also feels like it wants to stall as well. I think my car was at around 65k and it did the same. It is the spark plugs and the coil. My mistake was going to the dealership where they charge you too much. Any experienced mechanic can do it. Changing the coil is also in the manual.