Cylinder five misfire

BRETT WILSON2

MEMBER
2009 HYUNDAI AZERA
3.8L
V6
2WD
AUTOMATIC
46,000 MILES

Initially I got a code for throttle positioning sensor error followed by a code for a cylinder 5 misfire. TPS code never reappeared. Then I replaced the spark plugs and Ignition coils in all 6 spaces as well as the fuel intake gasket. Also replaced a upper coolant hose due to a leak. After this code went away for about 30 minutes of driving and then came back. Added fuel additive still driving on it. Code clears runs fine about half an hour afterwards but every time code comes back and shaking while idling and low RPMs (about 1200-1500) persists. I'm believing it's a fuel injector issue but this code disappearing and reappearing is unnerving.
One other symptoms is dimming dash and headlights during shaking bouts. Vacuum pressure is consistent.
Any ideas?

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,724 POSTS

Hi,

The idea that you see dimming lights could either be the result of lower RPM's or there could be an issue with the charging system. Newer vehicles are extremely reliant on proper voltages. If they get too low, anything can happen.

Do me a favor. I need you to check the alternator output when this happens. Here is a link that shows how to do it. All you will need is a voltmeter or a multimeter.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Make sure that when this is happening, that the RPM's aren't dropping too low.

One other thought is to have the can-bus system scanned. CAN stands for controller area network. This network ties several computers and modules together via a few wires. Here is a video that shows how it is done. Note that this scan should identify any of the modules containing codes and if there is an issue within the can-bus system.

https://youtu.be/InIlnsjOVFA

Let me know what you find or if you have other questions.

Take care and God Bless,

Joe