Having problem with my 99 Ranger 4.0, rough idle, rough starting. Bought it
last summer with 105,000 miles on it with unknown service past Problem is
sporadic sometimes idle is good and other times it's so rough that the truck
dies while backing out the drive (usually it's the worse when the engine is
cold). I have replaced MAF, idle control valve, plugs, plug wires and the
ignition coil; all with really no effect expect after replacing the MAF, the
truck has much more power but idle is sporadic with roughness.
In thinking back about the idle problem and having poor gas mileage, I
started thinking more on line of fuel issues; I bought a fuel pressure
tester and checked it. To my shock the fuel pressure is 65 lbs at idle, as
I understand according to my Chilton's book the pressure should be more like
30 lbs at idle. Would I be correct to replace the fuel pressure regulator?
to my understanding the regulator on the 99 is a non-returning regulator so
a plugged return line wouldn't be the issue.
Any thoughts on this?