Howdy,

I have a 2009 Elantra GLS with a 2.0L I4 and a four-speed automatic. It has about 214,000 miles now, of which most of the last 70,000 or so are highway. I have had some issues recently that I am not sure are related or entirely worth fixing at this point. I travel for work and reliable transportation is a must. This has been a great car for me and I have kept up with maintenance very well, but I am concerned it is near the end of the road.

These are the issues I've been having recently--

• Clunks hard into reverse, usually but not exclusively when engine is cold (Hyundai says this is normal)
• Occasionally will stall when put into reverse when engine is cold
• Idles low when the engine is warm
• Occasionally (maybe once a month) will search for gear while slowing down when approaching a stop or traffic circle
• When coming to a complete stop power will deep to ~500 rpm and the car does that thing where it shakes like it's going to stall, but it never has stalled in this situation
• When shifting into reverse I feel it shift, then the power dips very briefly (1 second at the most) similar to above, then engine speed returns to normal. This happens almost every time regardless of the engine being warmed up
• Probably once a day the rpms will dip randomly in the same fashion and immediately return to normal, all over the course of about half a second. This has happened in park, drive, and reverse but only while the car was still.

This is what I have done about these issues --

• Had motor mounts replaced about two years ago
• Cleaned throttle body
• Installed new spark plugs
• Installed new PCV valve
• Had transmission fluid changed and pan pulled by a trusted mechanic. No word but I heavily trust he would've said something if there was clutch or metal in it.
• Checked battery and alternator and they seem alright. Battery is excellent considering its age (3-4 years). I don't remember the exact numbers from each but they guy at Advance was knowledgable and we agreed it likely was a non-issue
• Replaced the valve cover with an exact fit from a scrapyard. New gasket and spark plug tube seals.

I have not noticed a drop in fuel efficiency, throttle response (not that it was fantastic anyway), and no warning lights have lit up. Yesterday it started a high pitch hum from the passenger side of the engine bay that I believe to be a pulley as the water pump was replaced with the timing belt at 200,000 miles. I don't expect this to be related. I apologize for the novel but thank you for help.