What’s wrong with this sentence?

I was driving to work, and my car runs out of gas.

The problem is that the writer started the sentence in the past tense (with was driving) and ended it in the present tense (with runs). If there is a logical reason for switching into another verb tense, it’s fine to do so. But what logical reason could this writer have? The sentence has two possible corrections:

Past tense: I was driving to work, and my car ran out of gas.

Present tense: I am driving to work, and my car runs out of gas.

Correct illogical changes in verb tense in these examples:

1. Archduke Franz Ferdinand of Austria was killed in Sarajevo in June 1914, and his assassination sets off World War I.

2. Marcus Garvey, who was the most influential black leader in the United States in the 1920s, advocates black separatism and leads a “back to Africa” movement.

3. Mars is the fourth planet in order of distance from the sun, and to the naked eye, it appeared to have a red-dish tint.

In 1, sets off should be set off; in 2, advocates should be advocated, and leads should be led; and in 3, appeared should be appears.

Logical changes in verb tense

What’s a good reason for switching verb tenses? Maybe you want to write about something that used to be true and no longer is. For example, you might write, “When I was a child, I wanted to watch cartoons bright and early every Saturday morning, but now, I like to sleep until noon.” The first clause describes something that was true in the past, so it’s natural to use the past tense; the second clause describes something that is true in the present, so it’s natural to use the present tense. This is not an example of illogical tense switching. The sentence would lack logic if the writer didn’t switch tenses.

But switching verb tenses without a good reason causes a lot of trouble for many students. In fact, if tenses are switched back and forth just a few times, a student’s paper can look much less organized than it really is. Any piece of writing that has illogical or inconsistent verb tenses seems incoherent; the writer appears to lack control of his or her material.