“My car shakes when I put it in drive” is a symptom we hear often. In a lot of cases, spark plugs can be the issue. Take a look at the black line on this spark plug, this is what we refer to as carbon tracking. This is when the spark does not go through the center of the spark plug but along the outside, creating a misfire. This particular condition could have been prevented, by simply replacing the spark plugs before they failed. Manufacturers vary greatly on when they recommend spark plugs should be replaced. If you have never replaced yours, give us a call and we can tell what the recommended milage is for your vehicle.