Volvo Repair: Ignition Problem, battery connections, type car

Question
240 volvo 1988 model with a B230F engine. Inconsistance sparking (firing)of plugs. This has caused car to be unreliable. The Plugs would fire properly than at the next turn of the ignition they would not. When I was firstly looking for answers I noticed that non-resitor plugs were being used. Would this have affected egine management? Note: the correct plugs are now installed. Any problem areas eslewhere you suggeat to look at?

Answer
there are many things that can cause this type problem.the different plugs would not affect the running.this type car did not normally have ignition problems so I can not suggest any common areas to look into.Iwouldstartwith checking fuses for corossion and battery connections thenn caheck the coil conections.