Salaam,
Rough engine behavious is caused by many stuff. Check ur coolant is not becoming like milk by mixing engine oil in coolant and vice versa. Also check your engine oil level is same and oil is not getting sticky. If these both are right then you engine head gasket need to be changed. As from where you saying that engine losing power and feel pick up has lost, this is the first thing looks like to check. As its free to check but most expensive to fix.
Then after that you can get your spark plug, coil and plug wire checked if any of these three is faulty then also engine get suffokate and lose power.