I have a 2000 F150 that I have been working on for my mother over the last couple days, thus far I have replaced the plastic vacuum line that runs from the intake manifold to the back of the manifold and the PCV valve, replaced the PCV valve, the upper intake manifold gasket, the IMRC bushing (the part that started it all...), the 3/8 hose that rots out on the back of the manifold to the PCV, all of the 3/8 vacuum hose I could find, and the plug wires for good measure. I am just trying to get this blasted thing inspectable, but it idles so poorly I know it's going to end up with a TC eventually. Can anyone point me in a direction to clear up this rough idle problem?

 

How many miles on what brand spark plugs? Inspect the coil pack carefully for cracks and carbon tracks. Replace the fuel filter and put some Techron in the gas. Clean the MAF. Remove and clean the throttle body and IAC. If you pull the plugs, do a compression test. Pull the EGR valve and make sure it's not sticking open. Check for DTC's, even though the CEL isn't on.

 

It's got 168k miles on it, the plugs are champion, but am far too terrified of cracking the plugs to replace them. I will do all the rest of your recommendations as soon as I get home. Thank you!

 

This is a good example of what it is sounding like. Kind of a rattling diesel sound with a lot of exhaust vibration.

 

You won't crack the plugs. If you have Champions in there, get them out and replace them with Motorcraft platinum. Don't use antiseize and torque them to 28 ft/lb.

Get that K&N off there and put a stock intake on it. Clean or replace the MAF sensor. Change the oil, use Motorcraft 5W20 or 5W30 with a Motorcraft filter.

 

AHH! The 4.2 doesn't use those awful plugs with the porcelain that extends into the engine that everybody has told me were in it! Sweet, I will pick up a set of those as well as they might have 100k miles on them for how well the prior owner maintained the vehicle. As for the oil, can that cause a rough idle? I mean I know its propper maintenance, but can that actually cause this problem??

 

I'm suggesting an oil change with the correct grade and filter because of all the clicking.

The plugs that break are only in the 04-08 3 valve 5.4 V-8. The 4.2 has "ordinary" plugs.

 

OK, idle smoothed out, still a little throaty sounding on the exhaust, I must just have a hole in something. I did get a random P1401 DFPE TC, but I cleared it and drove it for a half hour and it hasn't come back so far. As soon as I can get rid of this P1000 code this will finally not be my problem anymore!!

 

Check the EGR pipe where it attaches to the exhaust manifold, it has a tendency to rust out.

 

I will tell you the one thing I did on changing the plugs that made the HUGEST difference and made it 1000% easier than hanging upside in the engine bay, remove the inner fender wells and each front tire for each side. Yeah, its a bit of a pain, but I could comfortably sit and use a 3/8 ratchet and 6 inch extension for each plug and not bash the snot out of my knuckles or kill my abdomen from having to hang off the fender.

Plus you can then get a good close look at how good or bad the egr tube is from the passenger rear exhaust outlet.