Strange Problem with particles' dynamic

Hello everybody, I’ve a strange problem with particles, since shortly especially with dynamics. In fact when I launch the animation or the baking for the fist time, it works without any problem. But the second time, particles behaves weirdly. I have the same problem with hair dynamics, and particle collision. I found that it’s better to use small hairs to avoid errors, but I still have no idea of the way to obtain good particle simulation.
Problem-Particle.blend (1.79 MB)

If it continues, I will use rigid body simulation to explode my car instead of particles.

When working with particles it is best to always change the Cache Step from 10 to 1. This should solve your problem.

Oh. Thanks a lot, I love you, you don’t know how it will change my life for ever ^^

to be honest a cache step of 2 is usually ok , saves memory too, meaning more particles or a faster bake time.

the cache step refers to how often the baked results are factored into the final, like keyframing the camera, if you key every 10 frames, the movements isnt going to be “straight lines” but “smooth curves” , the same thing is happening in the particles, a cache step of 10 is like having a keyframe every 10 frames, meaning the inbetweens are going to be interpolated from the cache steps… this leads to odd results in a lot of circumstances, such as particles running along a surface, but means things like “fire” simulations, will look just fine with a higher cache step value (like the default of 10).