Engine problem
1997 Ford Expedition V8 Four Wheel Drive Manual 310000 miles

Folks, the mileage is in Kms.
The Truck has been awesome.
Codes have plagued me during the last 2 years...go figure with the mileage.
Anyway, all Coil packs, Injectors, Fuel pump in tank, O2 Sensors, and MAF Sensore has been replaced, and now I'm getting a P0175 Trouble COde.
In reviewing this site, I have kicked my own ass, as I fear that the K & N Filter I put in the truck two years ago is now the culprit....
The only other thing I can think of is a Vacum leak, which I am at a loss to determine how to check/pinpoint the leak.

Any ideas would be most welcome.

Cheers

Neil