I can't figure this one out. I changed the plugs (broke two of 8 - thanks Lisle) and changed the coils. Basically, I removed every tube and plug I could to get to the plugs and make it easier for me. I disconnected the hose on the driver side that runs from the intake valve to the throttle body (it looks like it goes there). When I start the car, there is a "hiss...hiss...hiss...hiss.." that sounds like it is coming from the nipple on top of the valve cover.

I've cleaned that hose, put some heavy grease on the nipple, made sure it was seated well, and I still get the "hiss...hiss...hiss". Have I plugged in a tube wrong somewhere? Is there a leak in this house I can't detect? I plugged an end and blew air threw it with the compressor and couldn't hear a leak. I've submerged it in water and blown air through it...no bubbles.

I'm lost, and any street cred I gained with my wife is evaporating quickly. Thank God I have the Bronco and the F150 to get us around.

 

OK, I checked hoses, replaced hoses, and the hissing is still coming out. Tried some things and it appears air is coming out around the #5 spark plug (front right/drivers side plug).

It was one that broke off and I removed. My buddy putting them in might have overtorqued it.

I'm guessing a helicoil is in my future. Should I use OR should I use
P.S. Money is in an object. Not a huge object. But I like to save.

 

Did a smoke test using a fog machine, press and seal, a Shop Vac attachment, and some gorilla tape. Looked like some smoke was coming from spark plug #5. Pulled the spark plug out and the threads were jacked near the bottom. Put a new spark plug in hoping it was the plug and not the cylinder threads. Put on the coil and started it up. The hissing stopped!

But...I'm still getting bogged down and the engine goes into failsafe mode with no throttle response. I'm thinking I hooked something up wrong. I can't find a picture or video of the 2006 Expedition engine compartment anywhere online. Anyone have a resource?

 

Update: After work, I hooked the Expedition up to a computer I borrowed from a friend. Cylinders 3, 6, and 7 didn't have their fuel injectors plugged in good. So, I checked all the connections and made sure they were plugged in well. The engine starts fine now, runs three seconds, goes into failsafe mode and you can hear the engine trying to suck in air. It's like the throttle body is open at the start, it runs a few seconds, and then the flap on the throttle body shuts and you can hear the engine sucking air around the throttle body.

I plugged in back in and got codes P2104 and P2111, but all they say is that the throttle is stuck open. Tonight, I'm going to test the electrical output of the TPS and also clean the throttle body and see if it helps. If not, I'm at a loss...again.

 

http://www.google.com/search?q=2006+...w=1259&bih=750

 

Did you clear the codes out with the scanner or disconnect the battery for a little bit and see if the same codes returned? Clean the connections for the tps and make sure all the wires are good. I looked online real quick and it looks like it's fairly common for the tb's to go out on those years and have to be replaced. Hopefully that isn't the case...

 

After researching it some this morning and thinking about it, I've come to the realization that it is probably the throttle position sensor that is not plugged in well. I thought that is what I was plugging in good on the driver's side last night, but I just found out that the TPS is on the passenger side at the base of the throttle body. I haven't double-checked that one yet. If it was not connected well, it could give a reading that the throttle is wide open (code that I'm getting) and the PCM is overriding it and keeping it shut to protect the engine. It actually seems pretty simple.

I will say this...I have learned more about cars and how they work in the last few days than I have ever have before. It's actually pretty cool. Now, if I didn't have enough cars for drivers...well that would suck. However, I do, so I can take my time and do this one.

I'll update with progress tomorrow!

 

Good luck with it. That's why I have 4 vehicles lol. A spare for my spare and my other spare . Thing is they usually all have something wrong at the same time! Are you using an electrical cleaner or anything to clean the harnesses?

 

Starting fresh today. Going to unplug everything and plug it back in after cleaning it. Going to check every connection and every plug. Going to clean the throttle body. If this doesn't work, it's going to be a TPS and a throttle body change.

Not fun, but it may be what has to be done.

 

CRC makes a product specifically for electrical connections. It's a red can can. I think its like $5-7 and I've used it to clean home computers that the processors have burned up and left a sticky residue.

Don't use carburetor cleaner as it will turn rubber into goo.