More than Islam, Islamism (i.e. militants of a political islam, not to be confused with jihadism). I can't think of any muslim country where the islamists are not either one of the major political parties (if not in power), or were a major political force but have been banned, or are a major party to a civil war.
I am sure I am missing some countries and many nuances but from a quick glance at the map and wikipedia:
Morocco: the previous prime minister was from an islamist party (Justice and Development Party)
Algeria: islamists (FIS) outlawed when about to win 1992 elections
Tunisia: islamists are the largest political party (Ennahda)
Libya: islamist a party to the civil war
Egypt: islamists won the elections (Morsi) before a coup
Mali: islamists are party to the current war
Saudi Arabia: political islam in power
Syria: islamists major party to civil war
Jordan: were major political party but have been banned
Iraq: islamists major party to civil war
Turkey: Erdogan is effectively a muslim brother
Iran: political islam in power
Afghanistan: talibans just took power
Pakistan: political islam in power
Indonesia: islamist parties being outlawed
Now there are all sort of other forces at play in political instability: ethnic hatred, various economic interests, etc. But the steady rise of islamism across the muslim world is real, and has probably a much bigger influence on the stability of africa than current or past western meddlings. In many ways it is the communism of the XXI century, i.e. an ideology which has gained widespread support, wants to take power one way or another, is an enemy of modern, secular, freedom loving liberalism, is full of internal divisions but have this common goal of imposing the Sharia as the rule of law. But its influence seems to have been completely ignored by the cookie cutter response that any problem of the world should be attributed to the West, one way or another.