I drove more than 200 miles thru moutainous road. The road was paved but there were lots of up and down hills. Elantra didn't go well at the up hill. Since then, I noticed the engine ran rough first few minutes in the morning.

After 5 days later, I has to stop the car at the middle of a up hill and go then engine start shaking more. It was almost stop without pressing the gas pedal more than usual. I could drove few more minute to my parking lot. I checked the spark plugs. There was some wet liquid and some carbon accumulation around the plug tips. I cleaned the carbon by brush and put them back. Engine is still runing very rough and check engine light is mostly flashing and sometimes solid.

I am thinking of replacing the spark plugs. Is there any other idea?

I will appreciate for any comment

This post has been edited by stevenk: Jul 24 2008, 11:01 PM

Finally figured out! It was spark plug wire problem. With new wires, engine is absolutely happy now.

Good to see you figured it out. Flashing CEL's are bad!