Trip to dealer with P0301 code

[gathermewool]

A full drive cycle is NOT required to be completed if a fault is immediately active. For example, if you disconnect a sensor, expect the code for it to come up nearly immediately. Other faults may be intermittent and take longer than one drive cycle. A misfire is one of those codes that, if it's never shown up before, may never show up again.

Gotta love the Hyundai 5yr/60K bumper-bumper warranty. Sure beats the usual 3/36K where nothing goes wrong in that timeframe.

This would fall under the powertrain warranty if anything which, as you point out, is also longer than most makes.

 

[tiger862]

This is what is wrong with techs today. Customer has an intermittent code and tech checks codes with no code then sends it out the door. This is way I did it even under warranty as I first check codes then pending codes. I could look at scanner then if it is a misfire which most intermittent codes are (at least the ones I worked on) you read scanner data. You can easily see a cylinder misfire as it happens then diagnose. You also look to see how long since code was cleared. Most codes are misdiagnosed cause it gives you a parameter that is out not necessarily a part. Techs today see misfire on cylinder 1 they start with plug first then start throwing parts at it. Example is a Mustang I worked on that had been to numerous shops that tried to fix a PO175. I checked data stream which I noticed coolant temp was -40 degrees on a 90 degree day so I sold coolant sensor since it was defective. She already had fuel injector replaced, fuel pump and cat replaced but now recommended ECM. Customer was not happy with spending all this money without fixing car and was threatening to sue for her money back.

 

[Jetronic]

When I get that code on a Hyundai I move the coil to another cylinder and the spark plug to yet another. 90% of the time it's the coil, but have had a bad spark plug and a bad injector.