Low Idle Speed When Cold
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Senior User
Joined: Aug 2009
Posts: 304
Likes: 2
Low Idle Speed When Cold
I have a 99 F250 LD. When I first start the engine in the morning it won't Idle
above 500 rpm. Is it a vacuum leak, tps, or control module? I've checked
but couldn't find a vacuum leak. Could it be the EGR valve? When the engine gets to normal operating temp it's fine. Anyone with suggestions?
above 500 rpm. Is it a vacuum leak, tps, or control module? I've checked
but couldn't find a vacuum leak. Could it be the EGR valve? When the engine gets to normal operating temp it's fine. Anyone with suggestions?
Elder User
Joined: Jan 2008
Posts: 605
Likes: 1
When your engine is cold how is idle speed determined? Does it really matter if your cold or warm? Once you reach operating temp. what happens? Are you familiar with open loop and closed loop? What sensors are used in open loop? Which ones are employed in closed loop? Who does fuel control? Who does air control? Who is the master and who is the slave? Who leads and who follows? Once you have these answers you'll know the answer to your question.
