I have a 96 accord that I just bought. Lets first start off by saying this car has been sitting for like a year. I changed the oil and did the normal maint. but upon inital start up before the engine comes to normal op temp I get a little sputtering like it wants to stall but dosen't the tach jumps up to about 2000 down to about 500 but goes away once the car reaches normal op temp. what should I check?