Ignition is usually the easiest of the three to check because on most engines, all you have to do is pull off a plug wire and check for spark when the engine is cranked. On coil-over-plug DIS systems, there are no plug wires so you have to remove a coil and use a plug wire or adapter to check for a spark.
Stress can affect every part of your body. muscle aches, head aches, how your hair grows, the texture of your skin, it can affect your menstrual cycle.
A answered. Stress does affect the immune stress. Stress is often part to the flight and fight response of our sympathetic nervous system. It is designed to protect us and get us out of harm's way and danger in the short term.