I`m having boilover when I slow down or stop.

You need to find the cause of the boilover. The most common is a stuck thermostat. If that is not the problem, be sure that you have the proper mix of antifreeze and water in the radiator. Too little antifreeze can cause boilover. If neither of these is the issue, the problem could be a clogged radiator, bad cooling fan/fan motor, or in the worst case, a blown head gasket or cracked head or engine block.

How is the transaxle boot on that side?

see if the timing belt\chain is broke,normally when it brokes the car slow down and stops and dont start anymore.

Check that you have the full amount of anti-freeze in the expansion tank AND that it tests to -34 degrees below zero Fahrenheit.Weak anti-freeze allows boilover and then your heater won't work when level is low or it air locks.ALSO,your thermostat can be stuck shut and that will cause the above problem of boilover.
This boilover can break down your oil by the engine overheating.So check your oil level and change your filter. don-ohio

Does it overheat on you ??? If not,, try replacing the radiater cap..Make sure the vehicle is cold before removing the cap..If that doesnt do it,,and the vehicle not overheating,,you may have a small combustion leak..Like a head gasket..But first try the cap..

now you just had a boilover you need to just replace the filter and oil

fuel filter most likely

Sounds like a Vacumm leak. Check all Vacc lines.

sound like something killing your engine when was the last time that you change your fuel filter might be causing it..

a number of things is ck engin light on