Fuel type related to misfire?

dvanny

New LVC Member
Joined
Jun 7, 2015
Messages
7
Reaction score
0
Location
Manhattan
I've owned my 2001 LS v8 since the beginning of summer and have just recently learned I should be using premium fuel in this engine. I've previously been using regular unleaded. The engine light has been on since the coolant hose blew off due to rotted plastic. I have the cooling system repaired and the engine runs and maintains itself properly. However, a few codes are still triggering the light - P0171, P0174, and P0300. These read System too lean Bank 1, System too lean Bank 2, and Random/Multiple Cylinder Misfire, respectively. After doing a bit of research into these codes, I read a few articles that suggest poor fuel quality could be causing the misfire, and following the misfire the unburned oxygen would trick the O2 sensors into thinking the system is drawing in too lean. Could this be linked to using the "lesser" regular unleaded fuel over the premium?
 
Could this be linked to using the "lesser" regular unleaded fuel over the premium?

In a word, YES. When I first got my 2002 V6, the rear view mirror would vibrate at stop lights. After I filled the tank with 91 octane, that vibration has all but gone away. The OM clearly indicates the need for premium fuel.
 
The OM clearly indicates the need for premium fuel.

not to mention that big sticker on the inside of the fuel door...




however silly the use of inadequate fuel, the safe bet would be that your misfires are due to the standard LS issue.
 
the other two codes (lean on both sides) makes me think that you might also have a leak of air somewhere letting unmetered air into the engine.
 
also, with too low of octane, the high compression of this engine could cause the air/fuel mixture to ignite too early (detonation), but it still should burn the mix and not show a lean code...

I would expect the most common cause of LS relater misfires to not ignite the mixture at all, sending raw fuel into the catalytic converters and destroying them.



but thats just my $0,02
 
your misfires are due to the standard LS issue.

I haven't been involved with this vehicle long enough to know what common issues are. Could you please elaborate on what you mean by the standard LS issue?
 
I haven't been involved with this vehicle long enough to know what common issues are. Could you please elaborate on what you mean by the standard LS issue?

You probably really should at least read the stickies.
The most common LS issue is marginal COPs (Coil-On-Plug). In short, they become weak and misfire every now and then. This also damages the spark plug, so both the plug and the coil must be changed at the same time. Since all the coils start failing at close to the same time, it is recommended to change all of them (and all plugs) when the first signs of a problem are detected. Failure to do this quickly can result in damaged/destroyed catalytic converters (expensive). Next after that is possible engine damage. (raw gasoline washes oil off of cylinder walls and piston rings, severe wear follows)
 
Thank you all of you for your help and suggestions. I'll read through the stickies and see what I can uncover there and after doing some work on the car, I'll let you know what I end up with.
 

Members online

No members online now.
Back
Top