Hi XXXXXXX.

Thank you for asking your question on JustAnswer.

This problem is typically caused by EGR passages in the intake manifold becoming restricted. When this happens, one or two cylinders will get most of the EGR causing them to misfire.

To clean the carbon, remove the upper intake manifold to expose the runners of the lower intake.

Once the runners are exposed, the EGR passages will be visible. Clean the carbon from all passages and reassemble.

When reassembling, install the updated intake seals and isolator bolts to prevent any future lean codes due to intake vacuum leaks.

The engine misfiring will also cause the smell .

Hi XXXXXXX.

Thank you for asking your question on JustAnswer.

Yes once you correct the engine miss fire , this should give you back your normal power and poor fuel economy.

Hi XXXXXXX.

Thank you for asking your question on JustAnswer.

Thank you very much as well.