2011 Ford Focus hesitation

I have a friend with a intermittent issue that I am having trouble diagnosing. It's a 16V Zetec with 165K. It had all of the symptoms of the dreaded defunct in tank fuel pump problem that was recalled. This vehicle was out of the recall with the VIN.

It hesitates at "mid speed". It starts fine, idles great cold and hot, bur it seems to hesitate at around 40 MPH. The following have been done by others:

- Replacement of the coil packs (3K ago)

- Plugs and wires (1K ago)

- Fuel Filter (1K ago)

- Platinum plugs (1K ago)

She told me that the hesitation was getting worse and that the CEL was going on. I checked it and it threw a 301. Cylinder 1 misfire. I ran down the new plug wires and they were sparking well, eliminating the coil, new wires and plug as it almost looked new.

I am having trouble diagnosing a hesitation in a friend's vehicle and could use some help from someone much more experienced than myself.

It's a 2001 16V Zetec automatic with 165K that has started throwing CEL 301 (Cylinder 1 misfire codes). My friend told me that the vehicle would hesitate at around 40, then proceed up to highway speed then throw a CEL. I asked her about the history of related repairs and learned the following;

- Replaced coil pack less than 3K ago

- Replaced fuel filter 3K ago

- Replaced plugs and wires 1.5K ago

- Replaced PCV valve 4K ago

Someone was throwing parts at it to correct this problem, but it eventually got worse.

The vehicle had also been exempt from the dreaded Focus fuel pump recall back in 2003. All fuel flow at low speed under load as well as high speed seem to be within tolerance. There seems to be no falter except at around 40 MPH.

Since it was still getting worse and there were no local viable repair options available, I decided to take on the issue. I tested spark at cyl 1 and found it to be strong, eliminating the wires and coil. I pulled the plug and as a platinum plug, it still looked new. This left two things, the injector and an internal problem like a valve..

Without a compression tester and the overall smooth operation of the motor in every other condition, I took the injector route. I pulled the fuel rail and replaced the cyl 1 injector with a remanufactured one. I also replaced gaskets on the TB and the intake. While I was in there, I also replaced the DPFE sensor as I have heard of silly readings being fed back to the ECU to create a similar issue with a leak somewhere..

The overall condition from my friend is that things are much smoother and better (No CEL's) but she did mention that there is still a hesitation at around 40, although less than before.

My only guess at this point without a shop manual is that there is a vacuum leak somewhere. Next test is obviously compression, but my gauge is MIA.

As I'm at a loss and hate throwing money at parts in hope, but feel very close at this point, I would appreciate any advice to help out my friend..

Thanks in advance for your advice and help..