Hmm, maybe try doing something like this,
for(i=0; i<distance; i++)
{
create particle at vector(ent.x+i)
}
That code obviously wont work but it may be helpful for understanding the logic. You still may have a trailing effect if you move around fast enough though. Additionally, you could just make a model, give it a flame skin, then move the UV coordinates to give it a "burning" effect. In fact I remember a fire material somewhere in a recent AUM that may be useful to you. Cheers