2000 Solara engine replacement
 

Solara motor died after two bad bouts of overheating so mechanic said Let's out in whole new motor. He did. Trouble now is it balks at starting in the morning. Or after sitting for a few hours. It does start and then runs like a Toyota-perfect. Mechanic says may be Idle air control valve? He is stumped so far....any ideas out there?

Is this a V-6 engine?

Idle air valve controls idle RPM. Search internet for video's on how to clean it.

Also check the sensor that sends coolant temp to computer.

Problems cam or crank sensor can cause starting issues.

This is the four cylinder model.....I believe he cleaned air idle control thoroughly .....So the other items bear scrutiny. Rough start this morning
again but once it starts it runs all day like a Toyota should.

Did the old engine start up OK?