Had a check engine light come on this weekend both times were when I was accelerating up a steep mountain pass. The light would come on and then flash throughout acceleration. Eventually just staying on. The code said it was a Cylinder #4 misfire. Don't remember the code number though. This is the first time this has coded this code. Just recently replaced an o2 sensor that was coding Bank #2 Sensor #2. Any relation? And should I start with the plug or is this something bigger?
Misfire on 1999 GMC Yukon
by Visitor in Nampa, ID on February 03, 2011
ANSWER by rc parts , February 07, 2011
plugs and coil boots or wires should do it code would be p0304 cyl.4 mis detected
ANSWER by yukon 2 , June 12, 2012
no. 3 cylindar misfire with new plugs and wires.