Rough acceleration, collapsed PCV vacuum hose

[dylanborns]

'01 Escape V6, 150,000 miles.
Driving to work and noticed "stuttering" or misfire when giving it gas. Smooth at idle, and no check engine light or other idiot lights came on.
Got there, opened the hood and noticed the large diameter vacuum hose from the intake down to the PCV has a rubber elbow that connects to the intake. That rubber elbow was collapsed while the motor was running, and expanded to normal when I shut it down. It's the big hose that is collapsed on the right in the attached pic.
I called around and nobody has the hose in stock, so I ordered from RA, and the part will be here tomorrow. Unfortunately, I didn't notice the hose is a two piece with another lower hose which I didn't order at the same time. I did order it and it'll be here Monday.
I installed a new PCV valve and put the old hoses back on until the new parts come. The old PCV valve seemed fine and it clicked when I shook it, which I believe tells you it's ok.
So until those new hoses come in, is there anything else I should be checking?

[dylanborns]

I replaced the complete hose from intake to PCV and still have the stuttering on acceleration.

Any suggestions?

[dylanborns]

I may have figured it out, but I'm not 100% sure yet. Today, while driving, it didn't stutter until I was at idle sitting at stoplights. Then, after driving for awhile, when it got warmed up, it would do it while accelerating up a hill, and at idle.

So, when I got home I tried cleaning the MAF sensor. I followed directions I found online, and that didn't help. I started digging around more on the motor, and found the other intake vacuum boot on the top, backside of the motor was destroyed. A few years ago, I noticed the vacuum boot on the intake on the front of the motor was cracked, and I replaced that. I didn't think about checking that back boot. When I found it today, I could tell it was broken, and as I pulled on the plastic hose hooked to it, the rest of the boot stretched and tore like taffy.
You can see in the pics attached that there is a T coming off the air intake, with hard lines that run to the front and rear of the motor. The one running to the rear is the one that I missed that was toast as you can see in the second pic.

After replacing that boot, I disconnected the battery and let it sit for an hour. I then took it for a drive, and about a block away, at a stop, I had the stutter. After that, it didn't do it at all, so I don't know if the CPU worked through it, or if I just didn't drive it enough for it to start again. I'll take it out longer in the next few days and see what happens.

[65comet]

With the V6, there is a problem with the early catalytic converters that are part of the exhaust manifolds. The insides of them fall apart and send their guts on down to the main cat and clog it up. What usually happens next, besides the inability to accelerate properly, is that the exhaust backpressure will cause the EGR valve to explode. What I did was take off the main cat, drop the intake side of the converter against concrete and tap the outside with a hammer until all that ceramic junk fell out and when I looked through it at the sun I could see daylight again. This might not be your current problem, but something to check on.