Help with low power

[Only_in_a_yj]

Hello all. 2010 Navigator 5.4 3v with 186,000 miles. I recently noticed a significant decrease in power between about 1800 and 3000 rpms. The power picks up above that. It surged very bad when it started but is much smoother now after what's listed below, but still no power in that rpm range. I've list everything below that I've replaced or tested. Any help is greatly appreciated.

Replaced spark plugs
Replaced all COPs
New air filter
Cleaned MAF
Checked exhaust back pressure at first O2 sensor. About 1 psi at 3000 rpm
Cleaned throttle body
New thermostat. It was only reaching 185F before. Now 200F
Fuel pressure tested at 45-50psi when driving.
No obvious vacuum leaks.

 

[Only_in_a_yj]

My scan tool shows the system switching from "CL" during normal driving to OL-DRIVE" if the pedal is pushed past about half throttle. I assume this is open and closed loop but shouldn't it stay in closed loop once warmed up?

 

[07navi]

Replace the fuel filter.

 

[Only_in_a_yj]

Replace the fuel filter.

From what I've read this year vehicle doesn't have an in line serviceable filter. I've also crawled under and looked with no luck finding one.

 

[sjwelds]

From what I've read this year vehicle doesn't have an in line serviceable filter. I've also crawled under and looked with no luck finding one.

That would be correct.

 

[07navi]

That would be correct.

Does the 2007 have one?

 

[sjwelds]

Does the 2007 have one?

Yes, my old 08 had one.

 

[Bobmc]

Don't know if this F150 low power problem applies to your vehicle, but it might be worth a look inside/below the air filter. Some good talk on scan use also.

 

[Blksmk]

Vvt solenoid on the firewall ??

 

[Only_in_a_yj]

Are you t

Vvt solenoid on the firewall ??

Are you talking about the egr vacuum solenoid? Rockauto.com has Iine listed but I can't find an egr valve on this motor. Is there one somewhere?