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?

 

My 96 ES runs at about 1500 for about a minute or two. Yours seems to be a bit fast for a bit long.

 

In my case, the idle speecd and the engine temperature seems to move in similary pattern.

Whenthe temperature reaches to normal, The idle speed also get to the normal condition.
And it takes about 5 minutesin the morning ( these days), andnot more than1 minutesin the daytime.

The problem is that when idle speedis little high,the car is a little noisy and it's not comfortable to drive.
If I start the car whenengine is hot enough, the car gets normal idle in 1 second.

Myformer carmakes idleto a normal condtion in 2-3 seconds eventhe enginetemperature doesnotget hot enough. ( This is donebycomputer whichreadsthevalue of engine temperature sensor.)

I wonder that otherESsget to normal idlespeed only after the engine temperture gets tonormal
OR
the idle speed reaches normal even before the engine temperature get to normal.

Looking for valuable comments. Thanks.

 

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 !!!)

Any goodsuggetions?

 

I would do the Thermostat first. It is the cheapest of the two, and, I would think the most likely.