Well I'm new to a few things here. New to this forum. I'm also new to American made cars. New to trucks. And new to automatic transmissions. Imports have been generally less buggy for me, but I decided on the urging of my wife and in-laws to give Ford a try. I like the F-150 series as it fits my needs.

I just bought a 2002 F150 Lariat 5.4L v8 with 125k miles on the Odo.

I'm a bit of a mechanic and I love digging into engines, but if there's anything that my last car has taught me is that you can save lots of time and money asking questions.

I figured that most cars will operate the same way, but going from Subaru to Ford the only thing that's consistent is it's a combustion engine, has A/C, and power steering. Oh and it has spark plugs... lots of them (went from 4 cyl to 8 cyl)

Couple things I noticed that I just haven't the foggiest on how to fix.
1: my Idle tends to flux. Now I'm talking about it going from 450rpm at warm idle to 550 rpm and back again. It just "wiggles" up and down on about a 1 second cycle. The car drives great, and it doesn't stall or anything like that, but I like to keep an eye on things before they become problems. Is there anything I should be worried about/looking at? Someone said water in the spark plug holes in another thread... anything like that.

2: My main problem right now. I get A/C out of only the defrost. I have the automatic temp setup. Do I need a new Blend door or Blend door actuator or is this a vacuum leak? (or both). I also read that the RPM can flux when you have a vacuum leak, but does a vacuum leak in the HVAC affect the RPM?

3: Anyone know where to find a shop repair manual with exploded views and detailed instructions? I found one that pops up when you google "2002 Ford F150 repair manual" It seems distinctly lacking. It doesn't cover any of the trim or interior. It covers engine parts, but not much else. It doesn't have instructions or torque numbers for bolts you're replacing... Chilton and Haynes tend to be overly brief has anyone found uses for these?

 

I will help you with ac issue. Not blend door or actuator. Vacuum leak either in the engine bay or the trucks with the electronic controls have orings on the back of the ac control that go bad. Google eatc oring repair.
BTW you don't have any spark plugs, you have coil over plugs.

 

A vaccuum leak behind the HVAC will cause idle surge since the vacuum to control the climate control system comes from the engine air intake.

If you have a leak anywhere in the vacuum system it will bypass unregulated air in the intake and will cause surges at idle but not at high RPM's.

And by the way...you have spark plugs, the only difference is that instead of having only 2 coils with a set of wires you have a coil over each spark plug also know as a COP system.

Keep us posted.

 

First of all, You guys are awesome.
Second, thanks for screwing me up about coiled not-spark plugs. It seems like I have some reading to do now.

So:
I have no idea where anything is in this vehicle. I spent an hour identifying parts (just looking under the hood and on a creeper). I found and identified the Power steering module and the alternator...and the battery of course. The rest of it is still being identified.

Is the 2002 the one where the spark plugs break off?

Where is the Vacuum reservoir? I need to start tracing vacuum lines. Also, a lot of my vacuum lines are encased in coils and wraps of various kinds. Is it normal to cut off or strip off what I need to, to find the vacuum leak?

 

The break issue plugs are 04+ plugs so you are good. Your vacuum reservoir is behind your battery tray. These thin lines will crack over time

 

5.4's did have an issue of blowing plugs out of the heads though, aluminum heads with metal plug threads causes the heads to expand more than the plug threads which isn't an issue as long as the plugs are properly torqued.

 

get a new pcv valve... motorcraft preferred. cheap and easy.

 

Agreed

 

What is the PCV valve a symptom of? Is it just good to change them out from time to time or is it due to something I've been talking about?

 

Your rough idle possibly but it is good to change them every 50k or so. You definitely have a vacuum leak as well so I would get that sorted first.