Land Rover Repair: 2003 Discovery Service Engine Light, land rover dealership, cheap plugs

Question
Okay, so, I have had my rover for almost a year.  Bought it with about 56K miles....at the 60K marker, I had my engine serviced....the very next day, the SERVICE ENGINE LIGHT came on....i called the Land Rover Dealership who serviced it and they said it was probably just the gas cap....so, now it has about 71K miles.  I have moved and never took it back to the dealership to have the Service Engine light cut off...today, I had a lot on my mind...busy with work...ran to the gas pump and accidently put just a tad bit of regular gas in it...my rover has been driving fine up until this point...I immediately stopped and put 93 gasoline in the vehicle and filled it up...very shortly after it started reving when I would drive it after being stopped at a red light...then as the day progressed it went away...tonight on the way home from dinner, it started "pulling" on mee as if it was sputtering while I was driving and the Service Soon Engine Light started flashing...went off and then started flashing again all the way home...doesn't sound good when i put it in Park and I am scared to drive it....what could it be?  Do I need to by some seafoam or something to put in the tank to clean the gasoline?  I barely put any 87 gasoline in it...barely...and where can I get some cheap spark plugs and wires...Cheap.,..I am funny huh?  There is nothing cheap about driving this vehicle.  Thanks for your help.  Sarah

Answer
low grade gas should not hurt your engine in the short term.  I doubt your issues are related.  Getting some water in the gas may have some of those effects, but hard to tell from where I sit.

Do NOT put cheap plugs and wires in.  You don't need the most expensive, as they're not always better, but don't go cheap, they'll cause more problems than they are worth.