i have a ford windstar about a month ago it start eating up gas then the check engine light came on so i took it to auto zone the code 1516 &0156 so i took it pit stop & was told i need to change the intake manifold runner control so i replace that the check engine light came back on the next day so they told me that i need to replace the o2 sensor so i replace the sensor light came back on the next day took it back and was told it is because of the gas cap put some vaseline on it & he turn off the light later that day it came back on so i took to auto zone & the code p0430 how come i didnt get this code before y after i got everything fix, did they do the sensor right and what could happen if i dont get it fix

First of all....don't just go replacing parts because the idiot at the local parts palace tells you too. If it was your gas cap (which didn't need replacing) it would have gone off after a couple of days. Secondly, NOW it may just be a leaky vacume hose. My '00 had one right up front. I put some electrical tape on it and light went off. Just because codes are showing up doesn't mean you need to replace parts. You will go broke buying parts you don't need. If your altenator is starting to go (which is common) you will start getting a bunch of different codes. If you changed battery without altenator, problems such as this are common. Altenators are not cheap. ($225) Find a reliable shop and stick with them. Also this site helps tremendously.

Rob