sennister
Full Member
Hello,
I was driving my truck down the highway today and after I punched it to accelerate around a car to take my exit I noticed that my check engine light was flashing. Knowing that the flashing check engine light means stop and since I was taking that exit anyhow I exited and turned off my radio so I could hear how the truck was running. Everything sounded fine and the light went out. I kept driving to the store that I was going to and on the way home I punched it again to see what happens. Again radio off from 55 to 70+ and the check engine light starts to flash. I got off the gas and it flashed for 5 sec and went out. The DIC was displaying no message. When I got home I connected my scan tool to see what what was stored. Under pending codes it reported P0300 Missfire Multiple Cylinders. I then started the truck and when though the computer to look at the data that has been logged. Here is what I found:
Cylinder Misfire Count
1 0
2 98
3 0
4 0
5 16
6 350
7 0
8 2
I have done some searches and found several postings of P0300 but most seem related to an aftermarket alarm or happen at idle. My condition only happens at WOT at higher RPMs (about 5000 RPM).
History of vehicle that I know of.
I bought it used in Jan. It has 62xxx miles. 2003 Z71. No Aftermarket Alarm. Everything stock except the K&N Filter. I did just do my first oil change on the truck and used Mobile 1 5w-30. I don't know what it had before but I would think dino oil. This oil change was a little over 3 weeks ago but this oil change was done right before I left for Japan. So the truck has been sitting in my driveway for the most of that time. I did tell my wife to drive it every now and then. I think she drove it about 3 times when I was gone on short trips to the store and what not. Also she drove it to work the day I came back so she could pick me and all my luggage up in the truck that has more room than the Audi and she reported no issues. This didn't surprise me as it only seems to happen at WOT. It currently has 1/4 tank of fuel.
I was thinking that it might be fuel as it has been sitting. But I would think it would take longer than 3 weeks for gas to go bad. I also read that contaminated fuel can cause this code but the primary cylinder that will have a missfire is Cylinder 7 and then 2 and 8. It was explained that these cylinders suffer from this because of how the fuel rail works. I do show misfires on 2 and 8 but 6 is my biggest offender not 7. So I'm not sure this is my problem. Another mention was injectors. I'm not sure about that though. As the light goes out I might keep an eye on it and see what happens after I refuel. I'm not going to clear the codes just yet in the event that I'm off to the dealer. It's a good thing that I insisted that the dealer included a drivetrain warranty because of the miles on the truck.
Thanks for any help you can provide.
I was driving my truck down the highway today and after I punched it to accelerate around a car to take my exit I noticed that my check engine light was flashing. Knowing that the flashing check engine light means stop and since I was taking that exit anyhow I exited and turned off my radio so I could hear how the truck was running. Everything sounded fine and the light went out. I kept driving to the store that I was going to and on the way home I punched it again to see what happens. Again radio off from 55 to 70+ and the check engine light starts to flash. I got off the gas and it flashed for 5 sec and went out. The DIC was displaying no message. When I got home I connected my scan tool to see what what was stored. Under pending codes it reported P0300 Missfire Multiple Cylinders. I then started the truck and when though the computer to look at the data that has been logged. Here is what I found:
Cylinder Misfire Count
1 0
2 98
3 0
4 0
5 16
6 350
7 0
8 2
I have done some searches and found several postings of P0300 but most seem related to an aftermarket alarm or happen at idle. My condition only happens at WOT at higher RPMs (about 5000 RPM).
History of vehicle that I know of.
I bought it used in Jan. It has 62xxx miles. 2003 Z71. No Aftermarket Alarm. Everything stock except the K&N Filter. I did just do my first oil change on the truck and used Mobile 1 5w-30. I don't know what it had before but I would think dino oil. This oil change was a little over 3 weeks ago but this oil change was done right before I left for Japan. So the truck has been sitting in my driveway for the most of that time. I did tell my wife to drive it every now and then. I think she drove it about 3 times when I was gone on short trips to the store and what not. Also she drove it to work the day I came back so she could pick me and all my luggage up in the truck that has more room than the Audi and she reported no issues. This didn't surprise me as it only seems to happen at WOT. It currently has 1/4 tank of fuel.
I was thinking that it might be fuel as it has been sitting. But I would think it would take longer than 3 weeks for gas to go bad. I also read that contaminated fuel can cause this code but the primary cylinder that will have a missfire is Cylinder 7 and then 2 and 8. It was explained that these cylinders suffer from this because of how the fuel rail works. I do show misfires on 2 and 8 but 6 is my biggest offender not 7. So I'm not sure this is my problem. Another mention was injectors. I'm not sure about that though. As the light goes out I might keep an eye on it and see what happens after I refuel. I'm not going to clear the codes just yet in the event that I'm off to the dealer. It's a good thing that I insisted that the dealer included a drivetrain warranty because of the miles on the truck.
Thanks for any help you can provide.