10 Ways You're Killing Your Car

PORTLAND, Ore. (TheStreet) -- If your "check engine" light could talk, it would hurl obscenities at you for ignoring it when it's only trying to help you out.

Your "check engine" light is your car's means of sitting you down for an intervention. It's trying to tell you that something's wrong and that you need to take action before it gets worse. Stop being afraid, suck it up and seek some help now before things get out of hand.

But you're not going to do that, are you? You're just going to hope that little LED bulb burns itself out so you can go about your business. Because how bad could it really be? You'd hear something, right? Then you could search "car banging noise" on YouTube and watch an instructional video on how to fix it yourself. You don't need a certified mechanic or an automaker's warning light telling you what to do. You're an independent, capable human being who just needs to get through this last commute and clear off some time on the weekend schedule for repairs.

Yeah, this is how car repairs increased for the second year in a row. According to car repair data site CarMD, repairs increased 6.7% overall last year, including a 13% uptick in labor costs and 3% increase in parts costs. In the Northeast and Midwest, where hardy folk who brave the cold regularly should know better, plummeting temperatures brought a 9% increase in average car repair costs last year.

CarMD just released its Vehicle Health Index and looked at what some of the most common "check engine" light repairs were in 2013. The sad fact is that most expensive common repairs could have been prevented by simple, inexpensive, routine maintenance. But since everybody's an expert, here are the problems that all of you self-certified mechanics failed to diagnose within the past year:

10. "Inspect For Faulty Vacuum Hose and Replace As Necessary"
Average repair costs:
$122
Percentage of all "check engine light" repairs: 2.22%
Change in repair cost from a year ago: +14.1%

The hoses connect to the intake manifold and vacuum the extra air from parts of the engine. Vacuum hoses heat up when the engine is running. When they heat, they can crack and leak. This lets excess air get into the engine and can cause engine hesitation, stalling and rough idling, plus damage to the oxygen sensor and eventually the engine itself.

While it's true  a mechanic will charge an average $122 to fix such an issue, you can make that same fix yourself for as little as $5.

9. "Replace Exhaust Gas Recirculation (EGR) Valve and Clean All EGR Ports"
Average repair costs: $351.97
Percentage of all "check engine light" repairs: 2.32%
Change in repair cost from a year ago: +7.9%

EGR helps your car run more efficiently and helps control emissions. The EGR valve recirculates a portion of the exhaust back through the combustion process, lowering the combustion temperature and the formation of nitrous oxide emissions. A faulty EGR valve or blocked EGR passage can cause rough idling, engine hesitation, misfire and poor fuel economy.

Basically, it can end up costing you whether it stays in or it comes out. It's one of the more expensive fixes on this list, but it beats losing a big chunk of your performance and gas money to a valve.

8. "Inspect Battery and Charging System and Repair/Replace as Necessary"
Average repair costs: $110.82
Percentage of all "check engine light" repairs: 2.54%
Change in repair cost from a year ago: +10.1%

Thank your car's computer for this one. Increased sensitivity means computers monitoring voltage on charging systems will trip the check engine light when things are out of whack. That means a lot more cars in the shop, but it also means that we now know a lot more about why car batteries act up more than they did before.

The typical rule of thumb is to replace a car's battery every three years, though a whole lot of us will just wait until something happens before giving it serious consideration. Extreme cold and heat gives that three-year limit a little more urgency, though, and may even decrease it depending on how you're treating your car.

7. "Replace Ignition Coil(s) and Spark Plug(s) if needed"
Average repair costs: 
$420.34
Percentage of all "check engine light" repairs: 
2.89%
Change in repair cost from a year ago: 
+32.7%

Yow.

Just look at that cost. Look at it and realize it could have been a tiny fraction of that if you took the time to simply replace a cheap little part such as a spark plug. Instead, you let it snowball until your ignition coil was shot and now it costs you upward of $400 to get everything fixed. Come on, you're better than this. Just replace a spark plug when the light comes on or, if you can't get to it yourself, have it looked at on your next tune up or oil change.

6. "Replace Ignition Coil(s)"
Average repair costs: $250.94
Percentage of all "check engine light" repairs: 3%
Change in repair cost from a year ago: No change

That's the cost of replacing the ignition coil alone, but unless you're just someone who neglects spark plugs until something more expensive goes wrong, you shouldn't see this happen until well into your car's sunset years.

Ignition coils help the engine start and keep running by taking the battery's 12-volt current and step it up to ignite the spark plugs. Sometimes cars have just one, but there are vehicles that have one for each cylinder in the engine. Surprisingly, even this isn't always a fatal problem for your car. When it destroys your catalytic converter completely, then things get really costly.

5. "Replace Mass Air Flow (MAF) Sensor"
Average repair costs: $423.61
Percentage of all "check engine light" repairs: 3.35%
Change in repair cost from a year ago: 3.2%

This is yet another issue that seems small at the outset, but can grab money out of your wallet every time you fill the tank.

The mass air flow sensor controls the air coming into your car's engine and determines how much fuel to inject into that engine. When it goes bad, your fuel economy can drop by 10% to 25%. That latter scenario is like heading to the gas station, putting three gallons into the tank and flushing a fourth gallon's worth of cash down the toilet in the disgusting restroom behind the station's convenience store. No, $423 isn't cheap, but neither is throwing that much cash away on gas you're squandering.

4. "Replace Spark Plug Wires and Spark Plugs"
Average repair costs: $361.95
Percentage of all "check engine light" repairs: 3.35%
Change in repair cost from a year ago: 5.7%

Seriously, stop ignoring that "check engine" light even when your car is running fine.

You see this nearly $362 price and say that responding to that light is expensive, but not when you know how to do the little things yourself. Seriously, the cost of fixing a spark plug shouldn't be more than $10. They make the combustion in your internal combustion engine happen and when they conk out, their misfires kill gas mileage and eventually destroy far more expensive parts. If you live in an especially cold part of the country, you probably already know the damage that cold can do to a spark plug. Fuel needs to vaporize for them to work and when it doesn't, those drops just gunk up the plug.

Please, just fix this and feel proud about a job well done. If you don't, you're going to have to deal with ...

3. "Replace Catalytic Converter(s) with new OE Catalytic Converter(s)"
Average repair costs: $1,154.23
Percentage of all "check engine light" repairs: 2.22%
Change in repair cost from a year ago: 6.1%

See, there it is. The most expensive repair on the list often caused by one of the least expensive parts to replace in your whole vehicle.

And more than 6% of you have this problem. Six percent who could have saved themselves a four-figure repair just by responding to an earlier issue instead of putting some tape over your "check engine" light or reducing it to a pleasant little beacon in the background -- ambient red mood lighting for your dashboard. That catalytic converter is one of the five most-stolen car parts in the U.S., according to AAA, just because the metals in it are so valuable. If you can't give it the same respect a thief or chop shop would, you deserve every bit of financial pain you get for abusing and ignoring it.

2. "Inspect for Loose Fuel Cap and Tighten or Replace as Necessary"
Average repair costs:
 $0.11
Percentage of all "check engine light" repairs:
 7.17%

Well, at least you're getting better about this.

Loose gas caps were 9% of all "check engine light" repairs in 2010. The overwhelming majority of them just needed to be tightened. If you're tightening it and it's still not working, a replacement is only a few bucks. Our advice: Put a little extra into it when you're done filling up. If you're in New Jersey or Oregon and aren't filling up yourselves, it may be worth your while to see what your fuel cap actually looks like so you're not troubling a mechanic with this more than once.

1. "Replace Oxygen Sensor(s) (O2S)"
Average repair costs:
$261.61
Percentage of all "check engine light" repairs: 7.55%
Change in repair cost from a year ago: -10.9%

It's a little sensor that's doing a lot, and there are a whole lot of ways to foul it up.

The O2 sensor measures the amount of unburned oxygen in the exhaust and tells a car's computer when there is either too much, or not enough fuel as compared with oxygen for ideal operation. But when you don't bring a car in for routine maintenance, skip oil changes and are missing things such as oil and coolant leaks, you're just inviting disaster.

Ignore that O2 sensor warning all you'd like, especially if it feels like there's nothing wrong with your car. It's just cutting your mileage by 40% and taking its toll on you in gas money. Why take a little pain upfront when the slow bleeding can last forever?

-- Written by Jason Notte in Portland, Ore.

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Jason Notte is a reporter for TheStreet. His writing has appeared in The New York Times, The Huffington Post, Esquire.com, Time Out New York, the Boston Herald, the Boston Phoenix, the Metro newspaper and the Colorado Springs Independent. He previously served as the political and global affairs editor for Metro U.S., layout editor for Boston Now, assistant news editor for the Herald News of West Paterson, N.J., editor of Go Out! Magazine in Hoboken, N.J., and copy editor and lifestyle editor at the Jersey Journal in Jersey City, N.J.

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