My daughter owns an 05 Escape, with the 3-0 liter engine.
Recently on her way home, the motor started making noises. It continued to run, and she looked at the gauges, and the only one that came on, was the check engine light.
She pulled over, and had it towed home. The local garage that looked at it, said the motor was blown, and it needed a new motor. The vehicle has 194,000 miles, and is in very nice shape.
I said I would look at it.
It starts up, and there is a lot of noise, on the top of the motor. With a mechanics stethoscope, I started listening, and the only place the noise is coming from, is the intake. Timing gear is silent, as is the lower engine.
I listen on the valve covers, and it's quiet. I listen on the plastic intake, and that's where I hear the noise. It's on all 6 cylinders.
I scanned the codes, and they are PO171, PO106, PO340, pO158, po2197, and PO2198.
I've looked up the codes, and understand what to look for, and have to admit, I have never worked on this type of motor before. If I do have to change motors, I can do that, but believe something fixable, has happened.
The motor never has been overheated, and always full of oil. There is no oil puddle under the motor.
Like I said, it does run, but surges, from barely running, to revving way up.
I removed the serpentine belt, to be sure nothing was dragging it down. It acts the same.
I was maybe thinking that something in the transmission, or torque converter may be doing something. I have not driven it, to see what happens.
Can someone give me some good advice, as to where to start looking.
Thank You, to any and all who respond.

 

I would start with pulling the plugs to see what they show (lean condition or rich condition). Could be cam synchronizer causing pre-ignition that the computer can't compensate for, intake leak that the system can't compensate for, fuel pressure among other items. But I would start with looking at the spark plug condition.

 

You may need to remove the intakes and see what you find. Sounds can be tricky and telegraph to other areas. A word of caution regarding switching engines, it has to be an exact replacement or you could open the box to unbelievable problems. Production changes are made not only from year to year, but also with the same model , same engine in the middle of a model year.

 

I was thinking maybe cat converter plugged up, so I split exhaust in front of the cat. Not sure if those big things on the exhaust manifolds, are resonators, or part of the catalyst.
Engine ran a bit more steady. Still noisy, but idle didn't jump up and down. stayed at same rpm. Stepped on gas pedal, and it bogged, and didn't want to rev up. I've read where an intake manifold may be broken inside the intake? Sprayed carb cleaner around intake area, when running. It didn't pick up rpms. Still searching.
Also using a mechanics stethoscope, the only noise I hear, is when I touch the lower intake, where it's bolted to the head.

 

I pulled the intake manifold off, and checked for cracks. I couldn't find any, but looking inside the manifold, it was wet, as if in a rich situation.
I pulled the plugs on it, and the rear plugs were a tan color, but to me, may have been running a bit lean. I pulled the front plugs, and they were wet and black, like they were running rich. The plugs seem to have a lot of wear, and if I can figure out the problem, I will install new plugs.
I guess the next step, is to pull the valve covers, and see what is going on.
I think if I find anything, it will be on the intake side, of one or both banks.
I've read where removing, then reinstalling cam caps and torqueing them, has quieted a noisy motor. But I don't want to believe that, unless I hear from someone who has done it, and was successful.
I'm really surprised, that I haven't heard more suggestions. Maybe there aren't that many problems with the 3.0, and no one has any first hand knowledge with them. I was sure I would find answers on this site.
Not complaining, just frustrated at not finding an obvious cause for this noise.