I recently noticed that my gas mileage has gone down termendously.then my check engine light came on and i had it diagnosed. It came up map sesnor. I replaced the sensor and my gas mileage started to improve.11/2- 2 weeks later the check engine light came back on and i once again i had it tested. Map sensor came back to be the problem. I was told the iat sensor and map sensor work together. My question is.....is that true and if so, is there a way to test that sensor. What other problem could it possibly be?