I have not, couldn't find the IAC valve. I thought that fly by wire models didn't have one, am I incorrect? If so, where is it located? Thank you!

 

So I found the leak with my new smoke tester! It's leaking on the side of the EGR valve, where the metal tube feeds into it from the engine. It's tight and I replaced the gasket last week, should I clean or purchase a new one? Thank you everyone, you've all been a huge help. Can't wait to hear back!

 

Would be super helpful to others if you could post a picture of where you found the leak.

Cheers

 

agree on request for pic. Actually, i'd be curious to hear which tester you got, and even see a video clip. I've considered buying a smoke tester but have not done so yet.

 

Actually I'm not sure, but NAPA has it on their site and shows "Guaranteed to fit your vehicle 2004 Ford F150 1/2 Ton - Pickup"

4.6L, 5.4L V-8 IAC Valve Replacement

How to Replace the IAC Valve on a 4.6L or 5.4L Ford F-150

The idle air control (IAC) valve is an electronically controlled valve that allows air to bypass the throttle body. At idle, the IAC is used to meter airflow around the throttle body so that the engine may run with the throttle blade closed, which is how the 4.6L and early 5.4L engines were designed to control idle speed (as opposed to opening the throttle blade slightly to maintain idle). Carbon deposits tend to buildup around the seat of the IAC valve, causing it to function improperly. Additionally, the motor controlling the valve's position may fail in time. Signs of a dirty or failed IAC valve include engine stalling, stumbling, and/or poor idle quality. Replacing the IAC requires only basic hand tools and is not particularly time consuming.

Applicable Model Years: 1997 - 2010 Ford F-150, 4.6L & 5.4L V-8
1997 - 2003 Intake Air Control (IAC) Valve: Motorcraft CX1874
2004 - 2010 Intake Air Control (IAC) Valve: Ford 2L1Z-9F715-BA

 

​​​​​​​So I guess the older body style 2004 has idle air control valves and new body style doesn't, but instead has a throttle position sensor. Yay Ford lol

 

pictures coming soon!

 

Glad to hear you found a leak. We know it's satisfying, especially after sinking money into the new smoke detector.

I wouldn't replace the EGR valve yet. It may be okay. If it's leaking "where the metal tube feeds into it from the engine", my first thought is to fix this leak. Since you said it's tight though I'm puzzled. I don't understand why it would leak there if it's tight, unless the threads are stripped. Why do you think its leaking there. Are the threads stripped? Are you sure the leak isn't coming from below, where the EGR is connected to the engine?

 

yes, I'm sure. It was leaking where you bolt it up at, but unfortunately the problem still isn't solved. Got to smoke test again this weekend. I'm at my wits end. Going to throw the upstream o2 sensors in soon, hopefully I'll figure it out sooner than later. I've been trying to fix gaskets, seals and hoses. You wouldn't happen to know what the pcv breather valve is officially called would you? Been trying to find the part on sites but haven't had any luck... I thought that maybe the gasket on it was bad. It looks like an unheated, black pcv valve, but it's on the right sided valve cover. Behind the oil fill column. Thanks for the input, keep you posted!

 

You are a 2005 4.2. I do not have first hand experience with the 4.2 but in general the EGR tube end fittings (nut and threads) corrode/rust badly over time. My experience with EGR tubes has always been trouble. Michigan vehicles. The end fittings don't want to turn but assuming you are able to turn the nuts here is what I would do to lessen or eliminate the leak you detected.
Remove the tube from the truck and clean the threaded areas where it attaches to the exhaust manifold and egr valve with a wire brush and in extreme cases a triangular needle file. Clean the internal threads with a wire brush and air blow clean. Once the external threads are cleaned on the exhaust manifold, install nut and tighten by hand. Take a small hammer and tap on nut as you work it back and forth on the threads with the intent of making clockwise progress by knocking rust and debris from the threads. Eventually nut will progress and a wrench will be required to work it back and forth. Once you are satisfied that nut moves freely go to the EGR valve and repeat same procedure being carefully not to damage EGR valve. When you are satisfied with results apply a medium coat of "never-seeze" to the threaded connection and tighten both nuts securely. If leak is still present tighten further until leak is eliminated. In some extreme cases nuts had to be ground off with a cutting wheel and the egr tube had to be replaced.
These are my thought to help resolve the leak at the EGR valve tubing.