Hello fellow Ford drivers! This is my first post, I have been lurking around for awhile and have found this site quite helpful in the past, but now I need some interactive help from those with experience!
I have a 1996 F150 4x4, automatic with the 4.9L. The truck has 88,000 original miles, and NO rust. I bought the truck from the original owner who told me it needed a Crankshaft position sensor. I brought it home to find a reman distributor installed and the timing WAY off. I timed it ( more on that in a second) and it ran smoothly but with barely any power.
I replaced the Crankshaft Position Sensor, no change. I hooked up my timing light and advanced the timing to 14 degrees ( more again later ) and it ran with noticeable more power , especially under 2500 RPM. But it still was a dog above that RPM
Thinking about this , knowing its a timing/iginition issue, I replaced the Spark plugs, gapped at .45 per factory specs , replaced the distributor , wires and cap and rotor with the best parts. It still ran the same. The spark plugs had a light brownish color indicating that the engine is running lean.Now to the timing Snafu:
When I time the engine, the harmonic balancer has a notch in it assuming its for TDC. The ring mounted behind if for the Crankshaft Position Sensor also has two pickup points and one of them is what Ive been using all along as a timing reference. The harmonic balancer itself currently has no marks even 180 degrees close to the nub I am using on the CPS ring for timing. The truck runs smooth, starts everytime well, gets horrible gas mileage ( like 10-12 mpg) and has good power under say 3000 RPM but still doesnt seem to have the power it should.
No check engine lights, the only thing that is changed from the factory is the Air tube going down to between the two converters is removed as is rusted off. I welded the hole shut on the exhaust pipe, thats it.
I'm not that familiar with the fuel injected ones, but on the carb models the dampener has a rubber piece in the middle of it. If the outer part of the dampener should happen to slip your timing marks on the dampener would not be correct. You may check to see if there is a repair manual that can give you more detail about the timing.
I've never had a fuel injected six but on the carb models if it is stock your not going to have much higher rpm that 3000 rpm.
Sounds like you may be timing it wrong. Your using the timing indicator on the passenger side, right? You don't use the ones stamped into the timing cover on the driver side. I have no idea why those are there.
And that crankshaft sensor is nothing more than something for emissions control. It plays no part in timing or fuel.