Joined: Feb 2019

Posts: 1

Likes: 0

Model: Cherokee (XJ)

Just looking for advice on my next troubleshooting steps. I have a 98 xj 4.0 with 203k miles. Recently I replaced the head gasket due to a slight leak of exhaust fumes into my coolant reservoir. After driving it for about 300 miles afterwards I began getting a P301 ( cylinder 1 missfire code ). After running compression my numbers are 80,130,125,135,140,150 dry and 85,133,125,136,141,150 wet. The missfire only occurs intermittently and after the engine is at operating temp while at a still idle. I have read of some people having success using penetrating oil in the cylinders and an oil additive slong with wide open runs. I plan to do a leakdown test aswell, however I’m fairly sure this is a valve issue. Any advice or experience is greatly appreciate.