ENGINE DIES AT IDLE, AND HEATER FAN SPEED SLOWS AT IDLE. WHAT IS WRONG?
1999 Ford F-150
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?
Wednesday, February 15th, 2012 AT 7:22 PM
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.