Well, if it isn't one thing, it is another.....Took the RRS out for a long drive the other night trying to get the readiness codes to set for the smog test. Smog guy said drive it 30 to 40 miles on the highway at 50 mph, not to exceed 55 mph. I gave it little chance of working, but I gave it a shot. Sure enough, the readiness codes set and it passed smog! It was running incredibly well! Well that didn't last long.............Now, four days later I get a reduced performance notice and the CEL comes on. P0304-00 (EC) Cylinder 4 misfire detected. It is running pretty rough. Got home and parked it. I just ordered a few new coils and some new plugs from FCP Euro. Great prices and customer service, downside, shipping, won't be here for perhaps five business days (although in the past, their packages arrive pretty quickly). Stay tuned. I will report back shortly. Phil

2010 Range Rover Sport HSE Santorini Black (had it three or four years, running like new)
2010 Range Rover Sport HSE Stornaway Grey (recent acquisition)

 

well yet another bad coil and/or spark plug. my FCP Euro package arrived yesterday I swapped out the spark plug and ignition coil on cylinder 5. Much easier if you remove the side portion of the brake assembly box and the module that is mounted sitting upright on the engine side of the box, Remove two 8mm bolts and it will move out of the way. No need to disconnect any wires or plugs. The side cover has four or five slideover clips. The coil and spark plug are very easy to access. (remove the foam cover over the driver's side coils, You have to remove the oil cap and unweave the cover from the two or three pipes that run over the cover. Once swapped out, the truck purred again. Amazing what one misfiring cylinder can do to a V8 engine. The truck had been sitting for a week. (the front end did drop down while it was sitting. Next item on the list....).Got some Mobil1 5w20 last night. Prices are crazy right now. I bought some at Walmart 6 weeks ago, $22 for 5 quarts. Last night at Walmart, $29 for 5 quarts.....thankfully gas is only $5 a gallon.............

 

Its amazing that one bad ignition coil can cause the truck to have multiple misfires. Mine is doing the same thing literally. No smoke but runs roughly. Shows all 8 cylinder misfire and low pressure at the rail. I was thinking fuel pumps but I found out cylinder 2 has a bad coil even though I recently replaced them truck continued to run roughly. I think cylinder 2 has a defective coil so I'm gonna replace it and hope for luck. Thanks guys for this post.