Cadillac Repair: Idles Rough and Engine Light on, deville dhs, spark plug wire

Question
This issue occurred after pumping gas from QT. I immediately thought bad gas but my boyfriend says probly just a coincidence.

00' Deville DHS, idles rough and engine light on. At 1500 rpm the light flashes and continues till I come to a stop (light is steady).

The car runs fine meaning while moving around in town or on the freeway.

Cylinder 1 misfire so I looked at the coil packs (Fine) boots seem ok. I went ahead and switched the coil packs to see if the issue would move and it didnt. hmm.

-Rose from Texas

Answer
If switching the coil packs did NOTHING. This tells you that either you have a faulty spark plug wire and or a faulty spark plug in most cases.

As to the check engine light, I would install a can of DRY GAS in the gas tank just in case you got some water from the gas stations fuel pump.