Low rpm stumbling?

In reply to Antihero :

At least it's an easy fix. 

thatsnowinnebago said:

In reply to Antihero :

At least it's an easy fix. 

True, and i shouldnt have overthought it and just taken a look at it

A berkeleying spark plug is loose on one side, apparently instead of over thinking it i should have just looked at it. Since both banks are lean im betting theres one on the otherside thats a little loose. Hows that for a stupid problem ?

Ehh, maybe not. With a wasted spark ignition system each coil is hooked to two spark plugs, and if one of them goes open-circuit for whatever reason the other one will fail to fire as well. And since cars use oxygen sensors and not Air/Fuel Ratio sensors, the o2 just sees all the oxygen coming out of the non-firing cylinders (that didn't get combined with nitrogen or carbon because no combustion happened) and thinks the engine is running lean, thus driving the fuel trims rich and exacerbating the problem. 

Let us know if it actually fixes it.. 

Vigo said:

A berkeleying spark plug is loose on one side, apparently instead of over thinking it i should have just looked at it. Since both banks are lean im betting theres one on the otherside thats a little loose. Hows that for a stupid problem ?

Ehh, maybe not. With a wasted spark ignition system each coil is hooked to two spark plugs, and if one of them goes open-circuit for whatever reason the other one will fail to fire as well. And since cars use oxygen sensors and not Air/Fuel Ratio sensors, the o2 just sees all the oxygen coming out of the non-firing cylinders (that didn't get combined with nitrogen or carbon because no combustion happened) and thinks the engine is running lean, thus driving the fuel trims rich and exacerbating the problem. 

Let us know if it actually fixes it.. 

You were right, only one plug was loose and after tightening it up...no check engine light, no codes and fuel trim is way lower than before.

Im happy it was such an easy and low cost fix, sort of pissed at myself for not just looking right away even though busy life etc

In reply to Antihero :

Meh, no biggie. That’s how you become a better mechanic!

Antihero said:

Vigo said:

A berkeleying spark plug is loose on one side, apparently instead of over thinking it i should have just looked at it. Since both banks are lean im betting theres one on the otherside thats a little loose. Hows that for a stupid problem ?

Ehh, maybe not. With a wasted spark ignition system each coil is hooked to two spark plugs, and if one of them goes open-circuit for whatever reason the other one will fail to fire as well. And since cars use oxygen sensors and not Air/Fuel Ratio sensors, the o2 just sees all the oxygen coming out of the non-firing cylinders (that didn't get combined with nitrogen or carbon because no combustion happened) and thinks the engine is running lean, thus driving the fuel trims rich and exacerbating the problem. 

Let us know if it actually fixes it.. 

You were right, only one plug was loose and after tightening it up...no check engine light, no codes and fuel trim is way lower than before.

 

Im happy it was such an easy and low cost fix, sort of pissed at myself for not just looking right away even though busy life etc

 

Don't be mad that you missed it, be happy that it didn't spit the plug out along with the aluminum cyl head threads.

Recon1342 said:

In reply to Antihero :

Meh, no biggie. That’s how you become a better mechanic!

Very true

gearheadmb said:

Antihero said:

Vigo said:

A berkeleying spark plug is loose on one side, apparently instead of over thinking it i should have just looked at it. Since both banks are lean im betting theres one on the otherside thats a little loose. Hows that for a stupid problem ?

Ehh, maybe not. With a wasted spark ignition system each coil is hooked to two spark plugs, and if one of them goes open-circuit for whatever reason the other one will fail to fire as well. And since cars use oxygen sensors and not Air/Fuel Ratio sensors, the o2 just sees all the oxygen coming out of the non-firing cylinders (that didn't get combined with nitrogen or carbon because no combustion happened) and thinks the engine is running lean, thus driving the fuel trims rich and exacerbating the problem. 

Let us know if it actually fixes it.. 

You were right, only one plug was loose and after tightening it up...no check engine light, no codes and fuel trim is way lower than before.

 

Im happy it was such an easy and low cost fix, sort of pissed at myself for not just looking right away even though busy life etc

 

Don't be mad that you missed it, be happy that it didn't spit the plug out along with the aluminum cyl head threads.

You are not wrong there lol