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2004 F150 5.4 rough idle when cold

7525 Views 2 Replies 2 Participants Last post by  datajer
Have a 2004 F150 when fist start up in the morning after the rpm comes down I get a rought Idle but as the engine gets warrm the idle is smooth. if I hold the rpms back up to 1000 when cold the rpm's go up and down a little but runs fine when warm. Had it in shop and could find nothing wrong except on #3 showed a miss when cold, replaced coil pack and plug but still the same. Help !!!!
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Have you reset your PCM by disconnecting the negative battery lead for a minimum of 30 seconds? Sometimes they get hung up and need a refresh.
thanks for the information, I unhooked the battery cable as you suggested but didn't make any differance. forgot to mention fist post they also checked the injectiors and run a somke test which proved all good, checked also for vacuum leaks they said never found any or detected any, thanks for Your reply
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