I sure this has been answered out their somewhere, as it seems no rover issues are truly uniques, but I can't seem to find what I am looking for.

2004 Disco SE7, 96000 mi. Head gasket, wires (STI) and plugs, T-stat replaced 18 months ago. Regular oil changes no issues since HG replacement. No overheat, not losing coolant, small oil leak. No issues with cold start, fires right up every time.

Today driving down a bumpy dirt road in was driving great hit some hard bumps at speed and then noticed flashing SES. Few seconds later the codes came p1300, p0300, p0304, p0307, p0304, p0307. Progressively engine began running rougher, misfire, sputtering, very little power, sounding more like a diesel.

I limped home and got to reading. Can't seem to find what I need. Could a hard bump cause these issues or is something much bigger at work.

Thanks for your help.

 

I pulled the plugs (bosch platinum's) and there was a lot of build up on them. Used some carb cleaner to clean them up and reinstalled. All the same codes. It sound like i have an exhaust leak where the manifold meets the y-pipe on the passenger side Real loud when revved up and then cuts back to normal for a few seconds when throttle is let off. Still a rough Idle

Got a spark tester. Strong spark on #7 very weak on #4

Could this cause these issues?

 

I recently cleared the same codes by replacing the sparks and the wires. I used Bosch Platinum+4, Kingsborne wires and lots of patience! ;-]#