Idle at start, too fast, too long?

[JBBenson]

I have checked the site already, found some similar problems but not this one, maybe someone has encountered it:

1988 FJ62:
High idle at start, about 1100-1200 RPM, slows to normal 650-700, but takes approx 4-5 minutes to do so. Not sure if it is a vacuum leak, because it would not slow down at all, right? Could it be sticky throttle plate? Or water temp sensor?

Car never seems to really get hot anyway, if the thermostat is missing, could this be the cause? (not sure, got the car recently)

Once the car is warm runs perfectly. Starts right up as well, no problem there.

Very helpful responses on my last problem, thanks again...

 

[jwest]

Assuming you'ver ruled out all the simple things...

Could be a dirty throttle body.

It's worth while to clean regardless.
Do a search and see what you come up with. BTW, take note that a coolant line runs through the intake area so don't go pulling hoses you're not sure about.

.

 

[chitown40]

Most fuel injectged vehicles will idle higher at startup until the vehicle warms up. If you think you have a problem with the thermostat no working correctly, you should check it or replace it since that directly has to do with engine operating temps. Then you should address the idle problem if it fact you think there is one. Where are you at climate-wise?

 

[JBBenson]

I am in Los Angeles. Since I am new to LC's, I do not know what is "normal" for 3FE engines. It seems that it takes a little too long to warm up and slow down, from 1100 RPM to 700. I have inspected for leaks this morning and found none, but the intake assembly from the air cleaner to the throttle body has some (typical) cracks in the corrugated rubber hose, at the bottom. At start, and cold, these cracks could leak and lean out mix, and as it warms, could they swell closed? I had a similar problem on another FI car.

I am anyway replacing thermo, to be sure. Maybe I can just live with it, as it runs just fine otherwise. But it bugs me.