Check Engine Light Flashing

What it feels like

• The light blinks on and off while the engine runs rough
• The car shakes noticeably at the same time
• A loss of power that comes and goes
• A sulfur smell from the exhaust

Codes that usually produce this

• P0300 Random or Multiple Cylinder Misfire Detected Stop driving 2 weeks estimate
• P0301 Cylinder 1 Misfire Detected Stop driving 2 weeks estimate

Check these first, in this order

Free checks first. Nothing here costs money except the fuel you burn.

1. 1

   Pull over safely and read the codes with the engine off, noting pending codes as well as stored ones.

   What you'll seeA misfire code naming a cylinder or several. That is your starting point.

2. 2

   Check the misfire counters at idle with the scanner before driving anywhere else.

   What you'll seeCounters climbing. A single cylinder points at that coil or plug.

3. 3

   Look at the coil packs along the top of the valve cover for a burnt or cracked one.

   What you'll seeOne that looks different from its neighbors is the suspect.