Mechanics

ENGINE DIES AT IDLE, AND HEATER FAN SPEED SLOWS AT IDLE. WHAT IS WRONG?

1999 Ford F-150 • 19,500 miles

1999 Ford F150, 4.6L, 195,000 miles. The engine goes to a slow idle and then dies. At idle the heater fan slow down, like loss of power?
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Rjones
February 15, 2012.




Check ICV valve. Same as IAC. Are you saying idle slows fan or fan slows idle? Extra draw from alterantor does put a slightly higher load on engine. If it's too lean already this could slow down idle. Idle slowing down lowers output from alternator so fan itself gets less voltage and slows down.

Tiny
Fixitmr
Feb 15, 2012.


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