do you think a decent mechanic could pinpoint the actual problem for a set fee? I know diagnosis fees can vary from $50 to up towards $125. I am wondering if a good mechanic could actually pinpoint the problem before chasing ghosts. Someone who worked on my brakes, he was a certified mechanic and he happened to hear the noise when it was nowhere as bad as it is now, and he said it could be the valvetrain. I'm going to see about getting a certified mechanic to give the truck a good lookover and what not. I only have breakdown coverage on the truck so unless it breaks down, I still have to come out of the pocket for repairs and diagnostics.

 

Other than the added cost, there certainly would be no harm in having another set of eyes and ears on the truck. Noises are typically much easier to diagnose in person versus over the Internet.

If you find a shop with a smoke machine, that will help to identify any vacuum leaks. And a good mechanic's stethoscope and/or ChassisEar will help to locate valvetrain noise or an exhaust manifold leak. Of course a shop that has the right diagnostic tools needs to pay for those tools so their labor rate may be a bit higher than a less well equipped shop....

-Rod

 

I found out where the vacuum leak could be. I found the pcv valve/hose location, its on the rear of the passenger side valve cover. I could hear a hissing toward the back of the engine and sure enough the pcv hose is cracked and collapsed. So i ordered the hose and valve from amazon.com because even Ford dealer parts would probably have to order the hose. I got same day shipping because of amazon prime and parts should be here tomorrow Wednesday. could this be the cause of slight power loss/rough idle/shaking?

 

I heard if the pcv valve or hose are bad, it could cause pressure build up and bad fuel air mixture, hence hindered performance and rich fuel mixture.

 

Since you could hear hissing that bad PCV hose is likely more of a vacuum leak rather than just collapsed. As a leak you probably don't need to worry about it causing pressure build up, but as a leak would certainly lead to engine performance issues just like any other vacuum leak after the MAF.

Good find!

-Rod

 

okay got the new valve can't put it on, it looks like the old valve but doesn't have the housing the has the bolt holes. Also I busted either a heater hose connector or cooling hose connect, leaking coolant bad. Why does the new valve not have the housing to bolt it into the valve cover? I looked up the part and can't find any housing. its just the valve.

 

i managed to get the new valve into the housing but lost the 8mm bolts. don't know how to get new ones to specification. do you think the other sensors with 8mm bolts what have the same length of bolts? Also here are the pictures of what I broke.

 

 

ok I got everything back together truck still knocking and ticking with sluggish acceleration and I still hear a hissing sound towards the back of the motor near the egr and pcv valves . I tried vacuum leak testing by squirting carb cleaner near all the suspect areas and I didn't hear a change in idle. can a bad egr valve cause a vacuum leak that may be hard to detect?

 

An EGR valve that is not closing completely will have the symptoms of a vacuum leak since that's what it is. I don't recall if the valve is actuated by vacuum or if it's electrically actuated on the Aviator. If vacuum actuated, a leak on the diaphragm side would be a vacuum leak as well.

Depending on how much time you want to spend finding the hissing sound, you might want to consider finding a shop with a smoke machine vacuum leak detector and have them run a leak test.

-Rod

 

I see from your other post on the topic that you may be wanting to condemn the EGR valve since unplugging it had no effect on the way the engine is running.

I'd caution you that all that really suggests is that you do still have a vacuum leak somewhere, and it's apparently a pretty large one. If you have a large leak somewhere other than the EGR, then you unplug the EGR valve and create a new small leak, it's not going to have a huge effect on the overall leak. It's possible that the leak is due to the EGR valve/gasket, but I'd suggest a bit more diagnostics before buying an EGR valve and gasket.

-Rod

 

Yeah don't want to throw parts at a problem unless you are certain. That's why I haven't bought the egr valve yet. A massive vacuum leak could explain a lot. I'm guessing somewhere near the intake manifold maybe the gasket? I just have trouble trusting shops and it's so much money to have it looked at. I doubt anybody charging even just $75 for a diagnosis would be through enough to find an exact cause.*