You can tell by its name, throttle position sensor, that when you've got a problem with acceleration then it's likely a good place to start looking. Aside from the check engine light, which would likely be illuminated if you have a sensor malfunction, what you will notice is a slight delay in your acceleration or a stuttering/stalling type condition if you are at idle. These symptoms can also be the work of a faulty idle air control valve, but there's one very dangerous symptom that will definitely tell you that your throttle position sensor is bad: sudden increase in speed. Aside from a car that simply won't stop, there could be nothing more dangerous than a car that speeds up on its own. Typically, this happens when the TPS (throttle position sensor) tells the vehicle's ECU that the throttle isn't open far enough. The ECU will then respond by allowing more air/fuel mix into the combustion chambers and the car will go faster. At this point it is time to test the ECU through your OBD-II port, or take your car to a mechanic that can. If the test confirms a bad throttle position sensor, then you have to replace it with a new one.
Most of the new vehicles on the road today use electronic sensors to monitor and control the engine's output. Your throttle position sensor is attached to the throttle body, and monitors the position of the butterfly plates that open and close to let air into the intake manifold. It then tells the ECU how much fuel to deliver in order to most effectively and efficiently create powerful combustion. When it reads wide open throttle, it will usually tell your transmission (if it's automatic) to downshift. Any malfunction in this sensor could result in an imbalance of air or fuel in the mixture, causing fuel economy problems or emissions irregularities. It is critical that your TPS be in good working order so that you will pass your next emissions test. If you are not subject to emissions testing where you live, you will at least want to make sure you are getting the best gas mileage possible. That's part of the reason why the throttle position sensor was introduced: so that our engines would waste as little fuel as possible during normal operation.
Changing a bad throttle position sensor is not terribly complicated. If it is faulty, then you will first have a check engine light illuminated on your dashboard. An OBD-II diagnostic will confirm the TPS needs to be replaced. If so, the first step is to disconnect your battery cables and locate your throttle body. You will see multiple wire harnesses connected to it. A repair or owner's manual will tell you which one connects to the throttle position sensor. When you have figured that out, disconnect it and unbolt the sensor from the throttle body. You can now replace it with a new one, and re-flash your ECU. The check engine light should go away.
It is critical that your new replacement throttle position sensor be the best quality. At Car Parts Discount, we carry top name brands like Dorman, Standard Motor Products, Siemens, VDO, and many more. These manufacturers produce original equipment and aftermarket throttle position sensors for domestic and import vehicles, and they are all great. Not only can you buy them at a great price on our website, but we can ship it to you right away - saving time and money on your repair.