What are some indications of clogged fuel filter or pump going bad?

[JenCel]

Well that was pretty self explanatory eh, lol?

In the mornings or when the van has been sitting for LONG periods of time after I star the van I hear this noise. It is like this: oooom......oooooom........ooooooom......over and over then after the rpms start dropping a little (ya during these times when I start it it also revs up a little with no pushing on the gas at all. It also gives off a little bit of an exhaust maybe smell? I have no codes but one for the speed sensor otherwise all the ones that did come up that I have fixed have stayed fixed--knocking on wood.) the sound is gone. All day I wills tart up the van and it won't do it. Sometimes during idle I will hear a little ticking sound too. Sometimes.

Lately I have had an old issue come back: after starting with a normal temp engine I will have this drop and surge in the rpms as if it is gonna stall then it gets gas then up and down about 4-6 times then it idles a little high then it drops down and is okay. That has happened a few times lately.

I tried the Autozone website sounds/feels etc and some of these came back with fuel fiter as a possibility. Any thoughts from a real person?

Thanks,

Jennifer

[wiswind]

Problems with Idle speed are often caused by the IAC (Idle Air Control). When your foot is not on the accelerator, the IAC controls the air into the engine.....The IAC is controlled by the computer.
It sounds like your IAC is working.....but sticking.
FORD says not to clean it....but many of us have.....
If you have to replace it.....they are not very expensive.
Location, on top of the intake manifold....next to the throttle body.
Held in place by 2 small bolts, and has 1 electrical connector.
Can be bought at Advance Auto, Autozone, etc....as well as dealer.

Also, look for vaccum leaks.

If the fuel filter has not been changed in a while.....I would just change it.....Is not easy....you need a special tool to release the one end....Instructions on how to change it are posted in this forum.

Fuel pressure can be measured.....but if the pump is weak, the pressure would drop under load.....
I would eliminate the other possible causes first....as fuel pump replacement requires dropping the gas tank.

[JenCel]

I had a code for the IAC valve and have already a month ago taken it off and cleaned it out good. Would it already be sticking again? How could that much carbon get built up so fast? And why is there no code for it if it is sticking?

How do I check for vacuum leaks?

Thanks

[wiswind]

If the IAC is sticking again....then I would replace it.
As I recall....it is not an expensive part.
I am not saying for sure that it will fix the problem.....especially if there are any vaccum leaks

Finding vaccum leaks is not easy.
But your profile lists that you have a '98.....so you, like me ('96) do not have the upper intake manifold, and it's bolts, gaskets.....issues that are referred to in many posts.
I had a leak develop on the inside of the elbow that plugs into the top of the upper intake manifold....right next to the IAC. It goes back to the PCV valve.
Also, make sure that the line that goes from the front valve cover is intact to the flexible hose that goes from the air filter assembly to the throttle body.

There are many other places that a leak can happen.