you need to check the output on your alternator. If the engine's alternator doesn't put out a high enough voltage to power the ignition system then you will have a weak spark and an incomplete fuel burn that causes the hesitation. Additionally, it will kill the battery as the battery voltage will be used to supplement the low alternator output. Without a good source of electricity your other electrical components will not work properaly as well, such as the horn. the engine knock is from the poor spark quality.
You may have a worn or misadjusted drive belt or an alternator that needs to be replaced. don't be surprized if the battery has failed as well because the battery can only recover so many times before it is damaged from the low alternator output.
hope that helps