rough idle at start

[theAntihero]

Ive got a 91ranger with the 4.0 ohv and its recently started idling really rough for the 1st couple seconds on its first start of the day when its cooler, any ideas on what it could be?

The check engine light doesnt come on and the engine is healthy for being 215000 miles from new(doesnt smoke,burn oil although i am getting some lifter noise). It was recently resurrected form sitting the woods for 7 years so there has been some little issues that i needed to go thru(temp sensor gauge failed, ABS speed sensor failed,tach isnt working).

Thanks

 

[theAntihero]

UPDATE:

On a whim i punched the gas before starting it and now the rough idle at start has disapeared. I hit the gas only once and now everytime after that its been starting fine.

Any idea why?