I'm trying to track down my (admittedly) minor issues and my next problem is a sometimes (most of the time) rough idle as I am braking and near a stand still. The harder I brake the more pronounced the roughness is. Not much else to say...

ABS issue? I've had my brakes lock before, but I'm pretty sure I have ABS on my 2001 XLT 5-spd 2.5L RWD.

 

Check power brake vacuum hose and booster

Start truck
Take foot off the brake
Turn off engine, count to 10
Press brake pedal 3 times, should have "power assist" for all 3 then pedal will get hard, when no more stored vacuum is available
If pedal gets hard after 1 press then booster is leaking, need to replace it

 

What would that have to do with my idle being rough--almost like it needs a tune up (which I have done recently)? But I just did as you suggested and it did not get hard until the 4th press of the brake. So, (luckily) the booster should be good.

What else do you think, Ron, you helpful fella, you?

 

A leaking Power brake booster is a Vacuum leak when using the brakes to slow down, which is what you said: Rougher Idle When Braking

So I would check its vacuum hose and check valve as well, if it only happens when brake pedal is pressed

If the rough idle is there and foot is not on the brake then could be electrical, turn on head lights and see if idle changes
Could be dirty injectors, run a can of Seafoam or similar injector cleaner in the tank
Older spark plugs?

 

Ooh, oh, engine vacuum leak--I'm tracking. I thought there was a separate vacuum system for brakes (ignorant, I know), but now I'm thinking it all runs off of the engine vacuum. Yes, it's only rough when braking and nearing a stop.

So, any good links to educate myself, Ron? I'll do my due with Google, of course. How many vacuum hoses are there?

 

Its possible that, during braking, the engine sees braking, and idles down the engine. In doing so, the AIC is not functioning as it should.

You could rule that out by introducing a vac leak to keep idle consistent, unplug the AIC, and see if the brake-idle problem goes away.

Its a shot in the dark, but it's another thing to look at. You could also pull and plug the brake booster line and try the same test. Even if it doesn't seem like its causing a fault, doesn't mean it isn't part of the problem.

 

AIC? I'm not sure what that is. Do you mean IAC (Idle Air Control valve)?

I may end up just taking it up to Ford. When things get into messing with vacuum lines and hoses, I get nervous and feel I'm a little out of my depth.