I have been working away for 2 weeks, i left my s2 in the works compound, came back yesterday, checked oil, water & brake fluid, then started her up, sounds like she is running on 3, sounds like an impreza!

Help me please, what can it be?

water in somewhere? its just sat there for 2 weeks solid, then started up straight away, but sounds crap & i dont want to drive it far, it feels bogged down

Please give me some ideas, as i need to make a few trips this evening & dont want it running like this, many thanks in advance