I have a Honda Civic 2003 gx 1.7 liter vTec stick shift 4 cylinder. Just today I had to put oil in my car. Drove for about 5 minutes got to a light and when I shifted into first gear a white cloud of smoke came out the tailpipe, stopped and let it cool for about 3 hours (had to run an errand) turned the car back on and bum again the white cloud. When driving it, the car doesn't accelerate as it did before putting the oil. Any help what can it be ?
Does the white smoke smell sweet like antifreeze? The loss of power plus the white smoke points directly at a bad head gasket. They don't last forever and it sounds like yours just got used up (coincidentally right around the time that you changed the oil).
Head gaskets on those VTECs can be replaced in your garage. However, I wouldn't recommend the job to a novice. The steps aren't technically hard but it is critical that they be done correctly (e.g., setting the engine to top-dead-center).
If you haven't done this sort of work before, I'd recommend taking it to a shop that you trust. You'll pay far more for the labor than the parts (gaskets are pretty cheap) but you won't break your engine.