This is for 2001 Protege ES ( 2.0 Liter, sport type) ( I bought it a few days ago).
Whenthe car is started ina cold morning, the RPM goes up to 2000 and comes down verly slowly.
It takes about 3-5 minitues to reach to normal idle (around 700 RPM).
Actually, I am newcomer to US and someone said that this is normal FAST IDLE feature for emssion requirement in U.S.
As for my car in my country, It took 1-2 second to goes to normal idle evenin cold startat morning.
How about your car?
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That cold idle is a long time. I timed mine this morning and it was 33 seconds to normal idle speed.It was 50 degrees this morning. I'm not really sure how this is controlled on your car, but I would get it checked out. Yours is not right.
I surveyed protege5 manual and found related article. (Please see the attached one.)
I think that, if we assume there is not air intake and idle control problem, the problem is related to ECT sensor or thermostat.
I have two possible cases:
1) If thermostat is always open, it takes more time to warm up the engine (because it should warm up coolant in radiator, also). So, it takes more time to get to normal idle.
This case, I think, the starting RPM should be normal.
2) If ECT reads wrong lower temperatureand sends it to ECU, ECU triesto warm up the engine to higher temperature than needed. So,it takes more time.
This case, I think, the starting RPM should be higher.
Which one seem reasonable?
Anyway, replacingthose two partsneedssimilar proceduresand I can replace the two part at the same time. (But, ECT is quite expensive !!!)