changed plugs and wires because van was missing it idles fine has a little miss but when you drive it it jerks and misses very bad worse than before plugs were changed and for some reason the brake pedal when driving slow goes all the way to the floor when engine accelerated brake pedal ok help please

 

Giving you hell? That's what they are designed to do!

Actually, I think there is a vacuum leak and I would first check the brake booster hose.
Run the engine and listen for a hissing sound. You can use a length of (garden-)hose to pin-point where the hiss is coming from.

There could be another source of vacuum leak. Check anything that gets plugged into the intake system.

And then there are the infamous grommets for the isolator bolts.

Report back.

 

Ok yesterday I cleaned batterie terminals checked all vacuum hoses they were al fine then took coil off checked for cracks there were none cleans coil mounting surface and surface that it bolts to put wires back on van runs great no missing everything running fine thanks for the replies