My son's 2001 Elantra just started experiencing a weird problem. It starts fine, but after running for 12 minutes it will stall and won't restart. After letting it sit for 20-30 minutes, it will usually start and stay running. We live up north, so at first I thought there might be water in the fuel line so I had him put in some Heet. 20 minutes after adding the Heet, the car started fine and he was able to make the 2 hour drive home with no problems. When he got home I told him to gas up with the good stuff, then pour another can of Heet into the tank. Yesterday he was driving home from a nearby town and 10-15 minutes into the trip the car quit. He shifted into neutral and coasted to the side of the road. Fortunately, the car refired right away and he made it the remaining 10 minutes home with no problems. Today we were going to go for a ride but had to let the car warm up for a while because we had a bit of freezing rain last night. 12 minutes into warming the car up (while we were scraping the windows) the car suddenly quit. After 30 minutes, it started and ran fine. FYI, the car has almost 160K miles. Its latest tuneup was at 133K miles, and the latest timing belt change was also at 133K miles. The battery is one month old. As far as Heet, the first bottle was regular Heet, but the second bottle was Iso-Heet. I won't have a chance to get it hooked up to a code reader until tomorrow. I'll report back with anything I find there. In the mean time, if anybody has any suggestions I'd really appreciate it!

 

You have all the symptoms of a "gunked" gas tank. There will be no trouble codes I believe. Usually this happens in much older cars, but it's possible for your car since you have so many miles. Over time, gunk forms in a gas tank, especially if you use cheap gas, live in a cold climate, and perhaps it rains and snows a lot. Many times, the gunk will cling to the walls of the tank, and if it doesn't slosh around too much, and you keep the tank full a lot, it's usually ok. Sometimes people get "rear ended" and it knocks all the gunk loose, and these symptoms occur. Other times people let the tank get too low, and the fuel pump sucks up the gunk.

[align=left]The fix is to drop the tank, buy some commercial gas tank cleaning agent, make a big mess, pull out the fuel pump and clean the fuel pump screen. If you rather not drop the tank, you can just try pulling the fuel pump out and clean the screen, but that still leaves lots of gunk. In any event, you can pull out the pump and do an inspection (look inside the tank). Here's a link with great instruction to pull out the pump from inside the car:

http://www.elantraxd.com/DIY/fuel.php

Good luck, let us know what happens for future reference.
[/align]

 

When the car dies and refuses to start, does the engine still have spark and fuel to it?

 

To be sure, take it to Autozone for a free trouble code scan.

 

There was an oxygen sensor error code, but after the code was cleared out the same behavior was still present. The code did not reappear. I took the car to my local garage and at first they said they were having a hard time figuring it out, but had a few possiblities they were looking into. Yesterday they called and said I need a new coil pack. They said that one cylinder wasn't getting a full spark due to a crack (not sure it was in the coil pack case or plug wire), and when the car transitioned from high idle to low idle that cylinder couldn't handle it and caused the car to stall. It wouldn't restart again until the engine cooled enough that it would go into high idle after being started. Does that make sense? The coil pack isn't a cheap fix, and I sure don't want to replace a $250 part if it doesn't do the trick. I do trust the garage I took the car to; they've always been very up front, accurate, and fair. The coil pack answer sounds plausible. About a year ago the check engine light came on and the car starting running horribly. The error code at that time was a cylinder misfire. The problem was fixed and the car ran fine until now. Maybe the two issues are related. I'll have to dig through my receipts and see if the problem is occuring on the same cylinder. In the meantime, the coil pack is on order.

 

Very interesting, please keep us informed.

 

Forgot to follow up on this, but the coil pack did the trick. There was indeed a tiny crack that affected the spark. The car has been running like a top and now has over 166,000 miles on it.