1994 nissan sentra

[jamessands]

on startup my car idle high but it does not go down after a long time.can someone help me with a solution for this

[nissasin]

Throttle cable too tight, Throttle stop too high or Faulty idle air control valve. I would try in this order.

[nametakennow]

Just at startup? Warm starts as well or just cold?

Engines idle high on cold starts to get everything warmed up faster.

Otherwise check for a vac leak in addition to what was posted above.

[jamessands]

only at cold start. warm start all is fine

[nissasin]

How long is a long time with the idle being high at cold start? 1 minute, 5 minutes, 10 minutes?

It is definitely not your throttle cable, nor throttle stop. I'm starting to side more on the Idle Air or even possible coolant temp sensor. Depending on how severe the idle is I would base my level of concern accordingly.

[jamessands]

it is about 30mins to 45 mins and have to turn the car off before returns to a normal idle