Check engine light- lean bank

I had my engine diagnosed and got that code, also showed multiple misfires. I just bought the car used and found 2 different spark plugs with different heat ranges and they were also gapped differently. I put in 4 autolight platinum plugs, but check engine light came on again. Also am feeling some slght hesitation. Can anyone give me any advice I dont want to spend alot of money but if I have to I will, I want this car to last a LONG time.

Thanks......

In the vast majority of cases, simply cleaning the MAF sensor does the trick. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling.

what is the specific malfunction code number[s]?

John