Hi,

I just bought a 2004 Discovery, which I did knowing that it's in need of some work (105,000 miles).

The "Service Engine Soon" light is on. When the car is idling, the light illuminates continuously. When the car is in motion, the "SES" light flashes.

I took the car to a LR specialist and he ran a diagnostics which showed that cylinder 7 is constantly misfiring. The “Misfire Status Report” indicates 304 for CYL7, and 0 for all the others. “Engine Roughness” report shows 0.48 for CYL2, 5.30 for CYL7 and 0.00 for all the others.

“Fault Code Diagnostics” are as follows”

P0307 - emission relevant misfire cyl 7
P0300 - emission relevant misfire multiple cylinders
P0307 - catalyst damaging misfire cyl 7
P0300 - catalyst damaging misfire multiple cylinders


Now here’s the thing: the car had been sitting in the used car lot for months before I bought it. It had been driven only rarely, and for short distances, and with the bare minimum of fuel in the tank.

I spoke to the dealer’s mechanic, and he says the problem is that the car needs to be “driven.” A lot. And on highways (not NYC streets, where I live), and to push the accelerator hard to suck fuel through the engine. There’s a lot of soot built up around the spark plugs, and he says this is due to minimal driving, with low fuel, on city streets.

He recommends that I put one quart of Lucas Fuel Injector Cleaner into the tank and fill it up with gas. Then take the car on the highway and push the engine hard.

So I’m wondering if any of you out there has any thoughts, based on the information above. Does the mechanic’s analysis sound correct? Would you recommend the Lucas Fuel Injector Cleaner, or any other treatment instead / in addition?

Thanks so much (as always) for your help and tips. This is a great forum and has been helping me a lot!

 

Lucas, Seafoam, or Techron fuel treatment and a full tank of top tier premium fuel... The least amount of ethanol possible.

Are the plug wires grey? they could be original, could be possible that the high mile service hasn't been done according to schedule.

Could be anything from plugs, to wires, to injector clogged, to cam shaft/lifter/rocker issue

You don't want to be driving it when the SES light flashes.

Welcome aboard... be sure to read the top few pages of threads to see what you're in for!