99 ford windstar code p1131?

99 ford windstar code p1131?

It means the o2 sensor on bank 1 is trying to correct for a lean signal. If its a V6 engine with 2 exhaust manifolds, bank 1 is the cylinder head closest to the front of the van.Bank 2 would be the rear cylinder head closest to the firewall. If its a 4 cylinder with 1 exhaust manifold, it only has 1 cylinder head so bank 1 is anywhere on that cylinder head.Bank 1 o2 sensor is the one mounted in the exhaust manifold or precat. If it says Bank 1 below and you've got a v6, you need to check the components listed below on the cylinder head area located closest to the front of the van instead of checking the rear cylinder head area. There are a few causes for this code.
#1-vacuum leak bank 1
#2-fuel injector bank 1
#3-misfire bank 1
#4-faulty o2 sensor bank 1
The vacuum leak should be located on Bank 1 due to the code that's listed. If the code listed said it was Bank 2, then you would be checking around the Bank 2 area instead. The easiest way to check for a vacuum leak is by using carb cleaner.