I just installed a new battery on my 03 evo after the old one died on me while I was in LA and was just about to drive it around, but right after i got out the driveway the engine started having really bad idle after depressing the clutch from 1st where it would drop down to just above stalling... it would bog down then go back up towards 800 rmp and back down close to it stalling after i depress the clutch pedal. this only happened once before when i cleaned out my engine bay, but after running it for half an hour the car ran fine... I have no Idea why its doing this please help