97 Ford expedition 4.6 liter

New to this so if this is not allowed delete. I had this 97 Ford expedition come with trouble codes p0302/0303/0304/0401/0136/0161/1131 the first thing I done was look at my 02 sensors both up stream were switching but the down stream were 0.010 volts and 0.014 volts none responsive so after doing a few checks and find server vaccum leak and fixing it first I checked the 02s and replaced .now both my upstream switch and my down stream are stuck on .896 volts and .902 volts my mass air flow shows 1.13 volts at idle and 2.23 at wot the Hertz are 150 has anyone seen this before

Not sure if you are still in need of help but here goes! The P0302,3&4 are misfire codes, the P0401 is usually a DPFE sensor issue or lack of/insufficient EGR flow detected, the P0136 is 02B1S2 low volts (lean condition), the P0161 B2S2 Heater malfunction, and the P1131 is a lack of B1S1 switching (lean condition). It looks to me like you have two issues possibly. Usually, a heater circuit issue is the O2 sensor being faulty and or the fuse is blown. The other codes would lead me to believe you have a vacuum leak, most likely the intake plenum. Very common on the 4.6L engines with plastic upper intake plenums. With misfire codes on the bank one or passenger side head, I would focus in that area of the intake! I have also replaced a lot of DPFE sensors for the P0401 code also very common failure part. I would check for vacuum leaks, especially around the intake. Use the water test! It is pretty cool and much safer than propane! Also, what are your fuel trim readings? Anything above +10% or below -10% indicates a problem. Hope this helps! Jeff