In an effort to ensure that cars have optimal tire pressure for best fuel economy, tires on some cars contain sensors that “talk” to the car’s brain box, which illuminates a warning light when tire pressure is low. I learned about this high-tech system while attending the Automotive Oil Change Association show a couple years ago.

In making this list of power upgrades, we limited it to what most mechanically inclined people with a free weekend, an open garage stall and a few hundred bucks can perform.

Most people equate engine wear and deposits with a sudden, catastrophic engine failure that leaves you stranded alongside the road. In reality, wear and deposits are more likely to erode engine power and efficiency over time. Here’s how it works and what you can do about it.