I have a 2000 DII with 92,500 miles. About 1 week ago the check engine light came on because the engine temp gauge went hot. The light was on for 5 minutes and then shut off after the car was moving. Checked the fluid level and it was down. I added coolant and it has been fine for the last week. I drove the car for about 100 miles.

Today I washed the car and hosed the engine compartment down with a light spray from the hose. I then went out for a drive. About 5 minutes into the drive the engine started to sputter. The sputter is comes and goes. The “Service Engine Light” is solid for a while and then flashes and then sold again. At first I thought that something might have gotten wet so I continued. The sputtering continued. Drove the car to a friend that has a OBD reader and read code 307, Misfire Cylinder 7. Reset the error and drove home. Error back on. I removed the spark plug from rear cylinder on driver’s side. I’m believed that this is the Cylinder 7. The Champion RC11PYPB4 plug is black and has a large gap of .075. Looks old and warn but not fowled. I replaced the plug with a Bosch Platinum +4. When for another spin and got the same symptoms and error code.

I’ve never gotten around to performing the Seafoam flush or gas treatment. I did not replace the plug wire. I have a set of Magnecore wires and Bosch plugs on the shelf, just have not had the time to perform the service.

Any suggestions on what to do next? That is short of changing all the plugs and wires. Could it be an injector and the Seafoam treatment will help?

BIG g

 

I had the same P0307 and service engine soon light. I installed the magnecores yesterday and then had P0307, P0305 and P0304. This afternoon I installed the Bosch plugs and she runs great and no more service engine soon light. Probably need to get theMagnecores on...

 

There is you answer, 8 mm Magnecor wires and some Bosch Platium Plus 4 plugs.
You can reset the ECU and expect a problem to go away.

 

When the plug wires go bad the spark will get weak and then the plugs will fowl.
Replacing the plug did nothing, your plugs wires are the problem.
Time to pull the parts off the shelf and get dirty.