Voltage & idle decrease when backing down hill | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Voltage & idle decrease when backing down hill


January 30, 2006
Reaction score
City, State
Lynnwood, WA
Year, Model & Trim Level
'92 XLT
This little pecularity has been bugging me for years - maybe someone here has had it happen too. When I back down a hill and the engine is warm (i.e. going down a driveway right after starting), the voltmeter drops quite low, the idle decreases to about 500 and I can hear the pitch decrease in the sound of the electric fuel pump (which is quite audible on my car).

The alternator was wacky for years and I had it replaced, and just recently, replaced the idle air control motor, but this symptom still happens. The only thing that makes sense to me is that maybe, my fuel filter is a bit clogged and that causes the idle to drop and therefore the alternator output and fuel pump voltage to drop.

Like most of the other problems I've had with my X, this one tends to be intermittent as well. Sometimes, the same conditions don't cause any changes in the idle or voltage.

'92 XLT

well one thing is for sure with it in rev you tend to also be depressing the brake pedal and though it isnt much drain on a circuit i have noticed mine does the same thing along with just about every car i have had witch was capable of maintaing a low idel. i dont thing a restrected fuel filter would cause this ,.however if you dont know how long its been since you replaced it the go for it