Mileage, PCM Flash, and White Smoke

[428F250]

Hi. I bought a 2003 Excursion with a 6.0PSD in July. Since then, my mileage has been steadily decreasing, and it has been getting harder to start when it is cold. It takes about 3-5 seconds to crank over on the first start of the day, and it belches out a cloud of white smoke when it catches (then clears up immediately).

Here are a few details and background.

The dealer had the PCM flash updated before we bought it. The sticker says the update was BU7-FYF (or maybe 807-FYF?). Hard to tell from the handwriting.

The overhead showed 16.9 ave mpg when we got it, and it didn't change for the first two weeks we drove it around town.

I changed the oil and filter and both fuel filters after about two weeks. The fuel filters were filthy (wonder if they had ever been changed).

We took a long trip, and I reset the mileage calculator before we left. During about 1000 miles of highway driving it got about 18.5mpg!

Since we returned from the trip, we've been driving mostly around town and the mileage has been steadily decreasing (about 14.3mpg average now).

It has also been taking more time to start for the first start of the day, and it has started to belch a cloud of white smoke on that first startup.

I plan to clean the EGR valve first and then possibly take it to the dealer to check power balance.

I checked the oil this morning, and it may be 1/16 to 1/8 above the full line (hard to tell), but I can't smell any fuel on the dipstick.

My questions are:

Could the PCM reprogram have anything to do with the low mileage and difficulty starting cold?

Does this sound like an EGR issue?

Does this sound like an injector issue?

Thanks for your help,
Jay

[428F250]

Also, can anyone recommend a good dealer in the SF Bay area to do work on the PS Diesel?

Thanks,
Jay