| When you purchase a used or pre-owned car, truck, | | | | pump can play a role as can a clogged catalytic |
| or SUV, and order a vehicle history report, you may | | | | converter. The manifold absolute pressure (MAP) |
| see an item on the report labeled "drivability." It will | | | | sensor may be faulty or the exhaust gas recirculation |
| often be accompanied by a rating. This confuses a lot | | | | (EGR) system might be defective. There may also be |
| of people. Most drivers intuitively understand labels | | | | a vacuum leak impacting compression. |
| such as "4-wheel alignment," "coolant flushed," and "no | | | | Another problem similar to hesitation is an overall lack |
| structural damage." But, few know how to interpret | | | | of power under load. For instance, while pulling |
| "drivability." | | | | something heavy up a steep incline, it might seem as if |
| The term actually encompasses an assortment of | | | | your vehicle is running out of gasoline. The potential |
| criteria that measure a car's responsiveness to normal | | | | causes of this issue are the same as those which |
| driving conditions. It includes cold starts, "no crank" | | | | cause hesitation: obstructed catalytic converter, failing |
| conditions, hesitation, and similar performance issues. | | | | fuel pump, EGR problems, etc. |
| Below, we'll take a closer look at each of the main | | | | Misfiring Under Load |
| areas addressed by a vehicle's drivability rating. You'll | | | | If your vehicle begins to misfire when accelerating, the |
| find the following information valuable in the event you | | | | issue will usually involve a vacuum leak. Fortunately, |
| decide to shop for a pre-owned car. | | | | vacuum leaks can often be resolved easily by |
| Does The Engine Crank? | | | | replacing hoses that have become worn and begun to |
| If the engine fails to crank, the culprit is likely the starter | | | | deteriorate. The challenge is finding the location of the |
| or the battery. Starter problems often develop | | | | leak. |
| gradually. You may start noticing a slow crank | | | | There are also many other potential causes for a |
| condition or odd sounds coming from the starter. | | | | misfire under load. A clogged fuel injector, bad spark |
| Issues related to the battery can range from a lack of | | | | plugs, failing ignition coil, and a weak fuel pump can |
| juice to poor connections due to corrosion. | | | | each contribute to the problem. |
| It Cranks, But Fails To Start | | | | Temperature Related Drivability Issues |
| If your vehicle's engine cranks, but does not start, the | | | | If you notice your vehicle experiences problems only |
| problem involves the spark, fuel delivery, or | | | | when the temperature is hot, the issue may involve a |
| compression. For example, your ignition system might | | | | shorting circuit board. This, in turn, can impact the |
| be malfunctioning; your fuel pump may be failing; you | | | | powertrain control module (PCM), which helps manage |
| may have a vacuum leak reducing compression. Each | | | | spark timing, emissions, oxygen sensors, and other |
| of these factors will prevent your car from starting | | | | systems. |
| even if the engine manages to turns over. | | | | Your vehicle's drivability encompasses a variety of |
| The Car Stalls Out And Dies | | | | potential conditions that affect its operation. Each |
| Suppose your engine turns over and your car starts, | | | | problem, as briefly described above, might be caused |
| but it stalls shortly thereafter. This type of situation | | | | by one of several factors. Identifying the culprit is not |
| suggests the ignition system is fine. However, | | | | always easy, especially in cases where multiple failing |
| something may be wrong with the fuel. The problem | | | | components may be contributing to a given problem. |
| may involve the fuel pump, water-heavy gasoline, or a | | | | If you have experience working under the hood (and |
| failing relay. | | | | own a few special tools), you may be able to |
| Engine Hesitates When Accelerating | | | | diagnose and repair the underlying issues. Otherwise, |
| There are many factors that might contribute to | | | | plan to have a trained mechanic do the job for you. |
| hesitation while accelerating. For example, a failing fuel | | | | |