I figured it out, it's the "Spray cone" parameter. Default is 50 (I think) and earlier I initially changed it to 0 which didn't work. Just now I tried 360 and it was much better!

I set the "Speed" from 200 to 0 and it goes to the left. I tried 100 and it's better but it goes to the right and then to the left. Wierd! I tried setting "Speed randomizer" to 0 and it didn't help. I deleted the object and recreated it but that didn't help either. Any other things I can try?

Here's a screenshot of the properties. I've tried adjusting angle, Speed, Acceleration, etc

dropbox.com/s/qdl2qbabq5djx8q/2014-02-17%2010_22_37-Particle%20object%20does%20not%20stay%20but%20moves%20sideways%20-%20Scirra%20Forum.png

I'm creating a particle object for an explosion and everything works great EXCEPT the particle object moves to the right as its fading away! I want it to stay in place and cannot find a setting for this. The object I'm spawning from is stationary so I expected the particle to be stationary as well.