Host of small performance problems in 2006 Hyundai Elantra

Question

I bought a used 2006 Hyundai Elantra (Automatic) back in early 2011. At the time, I was needed to have a car quick, and it seemed like a good deal, but the longer that I've owned it, the more problems have been popping up. Most of these have been relatively small up until now, but there have been some more prevalent symptoms as of late that are starting to worry me.

The first problem I encountered was overflowing the evap canister. At the time, I didn't realize that this was caused by putting extra gas into the tank after the automatic pump shut off, as my previous car did not experience this problem when rounding the purchase to the next 50 cents. This cost frequent stalling when the purge valve opened. Once I figured out what was going on and burned off the extra gas, the car seemed to drive okay. I did not replace the canister.

Since then, beginning a few months after, I've had a bunch of tiny problems start popping up. I don't know what is and is not relevant, so I'm just going to list everything that I've observed:

• In general, the car doesn't have as much power as it did before. Turning on the AC makes takes an even bigger chunk out of the power, but it seems like to a large extent than other cars I have driven.
• If I take the car above about 55 MPH, the steering wheel and car start to shake left and right. This doesn't seem to be an alignment problem, as the car drives straight as an arrow for a good 5-10 seconds without any outside interaction on a regular road.
• In addition to the above, when accelerating, sometimes it feels like the bottom of the car is shaking back and forth below me. The best way I can describe this feeling is when you are going up the initial include on a roller-coaster being pulled by the chain.
• The car tends to idle very high when first turned on. Usually somewhere in the 1500 rpm range. If I let it sit for about 30 seconds or so, it will reduce back down to 900.
• The car will regularly idle very roughly when stopped.
• Once or twice, electronics in the car have shut off or acted funny. The stereo system cut out with a loud pop, and plugging in a phone occasionally causes the phone to reboot and act like it has lost all charge.
• Car sometimes shifts incredibly hard. In addition, sometimes this tugs on the steering wheel while the car is shifting.
• Occasional odd sounds from the car, sounds like possibly the frame shifting a bit or something like that?
• When shifting from park into reverse or drive, especially when on an incline, the car will sometimes make a clunk noise. When on a decent incline, the shifter is physically tough to put into gear.
• More recently, when making slow turns (such as pulling into a parking space), the car will make a loud clunk noise. I think this coming from the front passenger side of the car, but I don't know.

I've checked the engine readings, but didn't notice anything majorly out of the ordinary. Based on what I've already researched, here is what I've found

• Tranmission fluid may be low / need replaced (last I checked it was okay, but that was a few months ago)
• Engine mounts might be going bad and need to be replaced
• Transmission mounts might be going bad and need to be replaced
• CV Joins going bad and need to be replaced
• Check and replace shocks / struts, if needed
• General suspension issues

I'd like to know which of these (or anything else) seems most likely, so I can start checking them out and hopefully getting it fixed. I definitely don't want to wait until something really important actually breaks!

Answer 1

Quite the list you have there. I'm not sure about some of the issues but, maybe this will give you someplace to start.

In general, the car doesn't have as much power as it did before. Turning on the AC makes takes an even bigger chunk out of the power, but it seems like to a large extent than other cars I have driven.

The car will regularly idle very roughly when stopped.

I would start with the inexpensive things that probably need to be done whether they are the problem or not. In this case try changing the spark plugs and checking the spark plug wires. Change the air intake filter. Also change the pcv valve and the fuel filter. These are basic maintenance items but, they can have a profound effect on performance.

If I take the car above about 55 MPH, the steering wheel and car start to shake left and right. This doesn't seem to be an alignment problem, as the car drives straight as an arrow for a good 5-10 seconds without any outside interaction on a regular road. In addition to the above, when accelerating, sometimes it feels like the bottom of the car is shaking back and forth below me. The best way I can describe this feeling is when you are going up the initial include on a roller-coaster being pulled by the chain.

These symptoms could mean that your tires need to be balanced or that a tire or wheel is damaged. I've had that happen. Check that the tires aren't badly worn or damaged and then take them to get balanced.

The car tends to idle very high when first turned on. Usually somewhere in the 1500 rpm range. If I let it sit for about 30 seconds or so, it will reduce back down to 900.

This sounds normal and shouldn't be anything to cause concern. Really, you should let the idle even out before driving, just to let it get to operating temperature and get the oil flowing before a load is introduced on the engine. (I have searched but can't find any references to back this up. Hopefully someone can confirm that it's not just heresay.) EDIT - Mac commented below describing the opposite instructions from VW and Audi owner's manuals. It seems they recommend starting and driving away. Mac suggested that it is a good idea to take it easy on the engine until it warms up, however. Thanks, mac.

Once or twice, electronics in the car have shut off or acted funny. The stereo system cut out with a loud pop, and plugging in a phone occasionally causes the phone to reboot and act like it has lost all charge.

This could indicate an alternator or battery problem in my experience. It could also be that a circuit is overloaded although, I would think that would just blow a fuse. You can have your battery and alternator checked for free at a parts store.

Car sometimes shifts incredibly hard. In addition, sometimes this tugs on the steering wheel while the car is shifting.

When shifting from park into reverse or drive, especially when on an incline, the car will sometimes make a clunk noise. When on a decent incline, the shifter is physically tough to put into gear.

More recently, when making slow turns (such as pulling into a parking space), the car will make a loud clunk noise. I think this coming from the front passenger side of the car, but I don't know.

I don't know about this symptom. Sounds like your transmission might be wearing out in some regard. It sounds like one wheel gets power before the other one making the steering wheel jerk.

Occasional odd sounds from the car, sounds like possibly the frame shifting a bit or something like that?

If you have a combination of unbalanced tires and a wacky transmission all kinds of sounds are possible. You may find that the sounds disappear after other issues are remedied.

Hope that helps a little.

Answer 2

Your question is seriously long. I will try to help with just a few here.

1. Car is hard to shift into gear on inclines. Make sure your engage your parking brake prior to releasing your foot off the brake once you have parked and are ready to turn the car off. This will allow the brake to so the braking and holding job and not the transmission.

2. If you have a vibration at certain speeds, have your wheels and tires balanced and rotated and have them check the alignment and other basics while they are at it.

3. Get a thorough tune up.