I have an I30 2001, I had a bad coil pack which would cause missing, replaced pack, know I get P0171, P0174. When I start the car in cold weather the engine starts OK When the engine starts it goes to high idle (about 1500 rpm) after about 10 seconds it drops to 1100 rpm running a little rough, after about 15 seconds it goes back to high idle, this in neutral. After that the engine runs fine. The gas mileage is good, in fact on a long road trip I got about 30 mpg. While driving at highway speeds the check engine light goes on. When I check the error it is the P0171, P0174 error, I have changed the air filter, and cleaned the MAS with no difference. The car seems to run fine with or without the check engine light on or off. The car is never difficult to start. This missing problem only happens on a cold engine. I have 120,000 miles on the car. I cleared the code several time, and will return. Thanks for you help. Ron
Apr 10, 2009 at 9:32 AM
