96 Intrepid too rich(both banks)

My intrepid is a 1996 3.5L. My engine started running rough and fuel mileage went way down. The check engine light came on and i got the codes engine rich bank 1 and engine rich bank 2. Any ideas why it's running too rich?

My daughters 96 3.5 had the same problem.....................

Replace the intake gaskets.

Thanks for the tip.

Thre intake and plenum gaskets come in a set from Advance Auto Parts (Use the Felpro #MS95444 ONLY!!!) and cost about $6. Easy fix.

Don't use then cheap gasket as you will be replacing it sooner than you want.