Revs bouncing at 3000

[sporty313]

Here goes problem number 2,

When driving in any gear once i get to 3000 revs the car starts jumping and vibrating like the engines being limited, although this keeps me at a license saving 60mph in fifth its doing my head in when the revs creep up and cant overtake much, also the engine management light is on aswell this all started when
I left my car stupidly for 3 weeks and when i returned not suprisingly the battery was flat and since then has been stuggling to keep a charge

this isnt all that old a battery although im going to pick up a new one tomorrow to give that a try,....... I have heard that when leving a battery out of the car can cause a reboot of the ECU and possibly resolve my rev issue.... has anybody else heard of anything like this???

I have tried checking the spark plugs even replaced them and checked the coil but to no avail... any ideas??