Misfires on Bank 1 - 02 4.6is

[upallnight]

Originally Posted by johnqpublic99

Ok... I configured torque to show me the fuel trim for sensor 1 on bank 1 & 2 but for some reason only shows me the option for short term fuel on bank 1 only... the numbers vary continuously between +- 7 on both fuel trim when I'm running above idle. On multiple occasions, as I'm slowing down at a red light, sensor 1 bank 1 number goes really high (like +25)... coincidentally, as I stop at a red light, the component status window shows me falling into open loop "because of system failure" and the fuel trim goes to 0.0 on both banks. Once I get going again, I come back into closed loop operation and fuel trim numbers start showing up again.

One last thing... on the emissions readiness panel... everything shows ready except for CAT which is in not ready state.

DF

With a fuel trim of +25 that means the computer is adding fuel to the mixture and since this is occurring when you are slowing down, the vacuum is highest since the throttle plate is closed. With that high of a fuel trim, the computer is setting a check engine light on.

Can you monitor the fuel trim at idle? If you can locate the freeze frame option in Torque it will tell you what the engine data were when the check engine light was set.

I would say that you have a vacuum leak. Scanner Danner has a great video on Youtube for locating a vacuum leak with just a bottle of water. Since bank one is showing a high fuel trim I would check out the intake manifold gasket along bank 1. You can also have the engine smoke tested.

As for the emission readiness, did you clear any trouble code? If you did you will need to drive the X multiple times to change the readiness status. I would work on the high fuel trim and worry about the readiness later.

[johnqpublic99]

Originally Posted by upallnight

With a fuel trim of +25 that means the computer is adding fuel to the mixture and since this is occurring when you are slowing down, the vacuum is highest since the throttle plate is closed. With that high of a fuel trim, the computer is setting a check engine light on.

Can you monitor the fuel trim at idle? If you can locate the freeze frame option in Torque it will tell you what the engine data were when the check engine light was set.

I would say that you have a vacuum leak. Scanner Danner has a great video on Youtube for locating a vacuum leak with just a bottle of water. Since bank one is showing a high fuel trim I would check out the intake manifold gasket along bank 1. You can also have the engine smoke tested.

As for the emission readiness, did you clear any trouble code? If you did you will need to drive the X multiple times to change the readiness status. I would work on the high fuel trim and worry about the readiness later.

Can't see the fuel trim at idle as it goes into open loop... found the youtube video so I'll give that a try tonight... smoke test would definitely be next.

yes I did clear the codes once I changed the o2 sensors... so I'll keep driving till the CAT readiness goes into READY state

DF