A quick visual inspection can satisfy most doubts about the ignition system. Trace all of the spark plug wires and ensure that they are free of corrosion and fit tightly on the ends of the spark plugs. If the engine has a rough, loping sound to it, you can check for arcing by running the car in a darkened garage. If tiny arcs are visible along the plug wires, the current is not reaching the spark plug, and the plug wires need to be replaced. Check the battery and cables for abnormal amounts corrosion. If you own a voltage meter, you can test the battery and the alternator. When the car is off, the battery should read between 12 and 13 volts; while the car is running, if the alternator is working properly the reading should be around 14 volts, and should remain steady at different engine speeds. Also, check that the key fits snugly and turns smoothly in the ignition lock cylinder, and that the car starts without much effort.
Suspension System
The most frequently replaced components of a car’s suspension system are the shock absorbers or struts. (Many trucks and older cars have shocks, while newer passenger cars tend to have struts. The main difference is that struts usually bolt directly to the car at the top, while shocks are attached to ball joints at both ends. Both shocks and struts do essentially the same job.) To check the condition of the shocks, use your weight to bounce the back end of the car up and down several times. When you stop bouncing, the car should settle after only one or two more bounces on its own. Use the same method to check the front shocks. You can also visually inspect the shocks or struts for signs of leaking hydraulic fluid. If the car bounces more than a couple of times once you let go, or if there are signs of leakage, the shocks or struts will need to be replaced.
Another thing to look for is evidence of a bad alignment. If the tires show abnormal wear, it is best to have the alignment checked, to be sure that the culprit isn’t worn suspension components.