98 civic ex d16y8
the car starts up perfectly fine, idles fine, no CEL but when it gets warm and you rev it past 6000 rpm. it lefts off a little thin cloud of white smoke. when i stop and let it idle, i can see very light smoke out of the exhaust. There is no loss of oil or coolant.

I recently baught the car and havent had a chance to smog it yet. When i baught the car it didnt smoke, or I didn't notice it. I did use sea foam in the vacuum line (1/3) but have driven for 30 miles and cleaned the intake with carb cleaner. I have changed the pcv and air filter.

 

Sounds like a head gasket problem. Check your compression, and do a coolant system pressure test.

 

figured it out, i checked the compression and it was normal then i realized the miles i drove it werent enough for the sea foam to get out of the system. Crud had gone into my cat and stayed there and started to smoke when it got warm. I didnt allow it to burn off long enough. I took it on the freeway and did a few high RPM passes at WOT for about 40 miles and got back and it seemed to go away. When i first would try it, i would just start the car and drive to work which was only 2 miles away and didnt even warm up when i got there. now the hard pushing has pushed the stuff out of the cat and the car is fine