Q: I'm having fuel pump relay problems.

Hey there, thanks for writing in about your 2001 Jeep Grand Cherokee. It sounds like you have an intermittent connection issue caused by a loose fuse holding tabs. The black you see is carbon where the voltage is jumping a gap, like a spark plug. The carbon itself is not a good conductor and will interfere with the electrical flow. The RPM increase is caused by the temporary leaning of the air/fuel mixture.

Clean the contacts and the fuse throughly with electrical cleaner, dielectric grease, or petroleum jelly. You may want to use an old toothbrush or small brass brush to lightly scrub the connector.

Sometimes a very small dental style pick can be used to slightly bend the tabs back towards each other, so the furs will fit tightly. Using a bit of dielectric grease on the fuse and holder will help with corrosion and may help keep electrical arcing from causing excess carboning.

If you are unable to bend the tabs, you could try to sandwich old fuse blades between the good fuses blades and the connector to ensure good contact. Sometimes, if you are careful, you can slightly bend the tabs on the good fuse into a V shape to help with keep the electrical connection complete. Other than that, replacement of the fuse panel would be the ideal repair solution. If you need help with this repair, I suggest having a certified technician, like one from YourMechanic, correctly diagnose the stalling issue, verify the problem, and complete the repair for you.