So my 2000 saab 9-5 aero had the error code for cylinders 1 and 2 misfire, i did not notice anything different or wrong about the car and then the check engine light turned off, the following week i decided to change the spark plugs, the day after the check engine light came on and i plugged in my obd2 and got the same error code but yet again nothing seemed wrong with the car and then the day after the check engine light turned off once again. Should i just ignore this or what? also if it is the Direct Ignition are those $200 you see online legit and or safe to buy?