Two weeks ago I noticed blue smoke filling the cab on startup with windows down. It happened again two days later and again three days later. It only happens when my truck is parked at the end of my driveway. This puts the front and back of the truck level. It's happened once after three hours and over night for the others. The truck has had some problems. Mass airflow sensor, fuel rail sensor and excessive ticking from the right upper part of the engine. I'm bringing it back to the dealer. What could cause this intermittent problem on my 04 scab 5.4L with 25K miles that sounds like a soft diesel knock with excessive ticking.

 

My truck, 03, smoked on the occasion when I got it. Since I've had it, it's only done it a handful of times. I have not noticed my truck smokin in the last year or so. I guess it got over it. Sounds like you might have other problems though. Good Luck

 

The knocking is likely cam phasers

 

I have 01 Lightning that I have stored under a carport for the winter. I start it up and run it about 30-45 mins once every week, when it's getting real cold in the mornings and night (I live in Maryland) and leveling off at about high 30s-mid 40's in the afternoon.. I also get a small plume of blue smoke on start up everyonce in a while - Doesn't happen when it's driven on a more daily basis.

I'd assume it's the PCV system on my truck that everyone knows baout, I have yet to install an oil seperator.. Im sure part of it has to do with small amounts oil getting sucked into the intake and it works its way down eventually, thats why mine does it since it has a whole week to work its way into the cylinders.

All I can give you right now is to do a visual inspection on everything, clean if necessary - Especially around the intake and PCV/EGR area. If you're under warranty, wouldnt hurt to get it looked at.

My fuel injectors make a lot of noise at idle, more of a tick from the pulsing than a knock though.