my 95 F-150 with 55K 5.0L would do that when you would idle for a couple them romp on it while in neutral, but it would just be a small amount, nothing bad at all. I asked around back then and it seemed to be normal or nothing major at all. that truck made it to over 100K before I traded it in (for a car because I had to commute)

 

That's exactly how this is.

 

Smoke on start up, sounds like cracked head(s)

 

Would that only do it when you rev it up and it's not a lot of smoke just enough that you can notice it kind of poof out when you rev it up high. I don't notice it getting hot or anything else.

 

Have you been losing coolant? Smoke on start up is an indicator of cracked heads, maybe you could get your coolant system pressure tested.

 

Blue/White Smoke

A blue/white smoke is an indication that oil is being sucked into the combustion chambers through the valve guides. A quick fix for this problem is by replacing the valve seals. Valve seals are small, umbrella shaped pieces of rubber.

Black Smoke

Black exhaust smoke is usually caused by a high ratio of fuel to air. Your car should burn a balanced mixture of air and gasoline to make power, but if the ratio is too high, it can cause the black smoke. You will sometimes notice this on older vehicles after first being fired up.

White Smoke

If you see a wispy, lingering white smoke that has a bittersweet smell, this is an indication that your car's engine coolant is leaking into the combustion chambers. This may be due to a leaky head gasket, or in a worst case scenario, a cracked cylinder head.

Thick White Smoke

If your vehicle is belching white smoke upon start-up, it is a sign that transmission fluid is entering the combustion chambers, possibly though a vacuum tube that connects the engine to the transmission.

This type of smoke can be confused with the normal puff of steam during start-up. If you are not sure, have your car inspected at the shop.

I had white smoke pour out of my exhaust after a night of rain, I thought maybe my seals were going to need to be replaced, asked my dad he told me to run at 1500rpm for a min. Smoke poured out then completely stopped, turns out the "smoke" was steam from rain condesation.

 

Valve guides/seals is a possibility. How does your truck run? Does it run rough at idle? A cracked head or bad head gasket will make it run rough enough for the PCM to start throwing codes. Run a compression test if you have any doubts about your engine's condition.

 

It runs pretty good. No different than before and like I said hard to tell on the color of the smoke it's soo little. You can just see a little come out when you rev it up high. I have a compression tester but haven't tried it out yet so I may do that although I'm not sure. I don't notice it loosing coolant or getting hot or any other signs of as cracked head/head gasket. Seems to run great and only puts out a little smoke when you rev it way up. As in 4k or so rpms not like a slight tap of the gas go get up to like say 1-1500rpms.

 

It doesn't sound like anything serious at this point. However, I would go ahead and run a full compression test when you can just to establish baseline cylinder pressures. This data may come in handy if/when you run tests in the future. If you run the test, make sure you pull all the plugs and have the throttle blades wide open.

 

if its only a little when ur up high in the rpms, maybe ur A/F mixture is a little rich and ur just blowing some gas out.