One day, you go to start your vehicle and you notice it struggles a little to get started…then it runs a little rough. You experience lumpy idling and a faltering, bucking sensation while you accelerate Check Engine Light in Springfield MO with the Check Engine light on the dashboard illuminated. Why does this happen, seemingly out of nowhere?

There are many reasons why a vehicle might start running rough, but let’s consider a few basic ones right off the top. Consider that any internal combustion engine needs fuel, air, and spark to run. In the end, a rough running or misfire condition is going to come back to one of those three factors, so we can start a process of elimination:

Clogged air filter: an air filter that’s really dirty and clogged will obstruct airflow into the fuel system enough to halfway smother the engine and cause a misfire.

Clogged fuel injector: this is a problem that doesn’t happen often, but it doesn’t mean it’s completely unheard of, either. Along with a clogged injector, low fuel pressure in the injection system or a problem with a fuel rail can cause a misfire.

Vacuum leak: the engine’s controls rely on multiple vacuum connections as well as vacuum canisters, amplifiers, reservoirs and junctions for vacuum lines. A vacuum leak can be enough to cause a misfire and even log a trouble code in the engine computer.

Spark plug: while spark plugs only need to be changed at about the 75-100,000 mile mark these days, that doesn’t mean they *never* need to be changed. A worn set of plugs can cause a misfire.

Ignition: in the old days, running through a puddle could be enough to cause moisture or condensation to collect inside the distributor cap. Vehicles no longer use distributors and plug wires; most instead use a coil-on-plug setup to deliver spark right at the plug. These “coil packs” will often fail after a certain point (a common Ford problem) and cause rough running problems.

Of course, there are all sorts of possibilities that could account for a rough-running condition, hard-starting or misfire; these are just a few of the basic scenarios. Is your car running rough? Don’t put it off – make an appointment with us at JBC Tire Complete Auto Care in Springfield or Nixa, MO!