My 99 2.5l has recently been running very poorly. It threw a code for MAF sensor (P0102) and a cylinder 1 misfire. I cleaned the MAF, replaced the plugs, and will be looking into plug wires, replacing the MAF completely and other potential issues.

As I was diagnosing the issue I noticed a broken wire that was rubbing up against the fan belt. After looking at some pictures online it appears this was connected to a black box mounted onto the rusty bolthead marked in the picture. What is this wire and black box?

I drew arrows to the broken wire end, connector, and the rusty bolthead where I believe the wire was connected to a black box (relay?) based on pictures online. Thank you

 

The missing part is the radio noise suppression capacitor. Helps reduce ignition noise in your audio.

 

Thank you! So definitely nothing to do with the rough running issues I've been having. I just ordered a new MAF sensor and plug wires, hoping that resolves the issue!

 

Just out of curiosity, is it only running rough while your driving or is it at idle also? Or just one of the two? Wouldn't hurt to look at the IAC valve while you're at it. Sound like you have air and spark covered after that.