I own a 2004 12 valve Taurus (SOHC).

I recently had a code come up saying that I had a vacuum problem (P2197).

I ignored it, figuring that I would get to it later.

I finally brought it in to my mechanic when it developed a rough idle and really poor acceleration.

They checked it and determined that the problem was actually a defective coil pack.

Over the week that followed the replacement - the performance became worse and worse until the car could no longer go faster than 10 MPH and would not sustain an idle.

When the mechanic checked it - they found that there were a number of holes melted through the intake manifold.

I decided to replace the manifold myself today - and it is already starting to show the same problems (poor/rough idle - poor excelleration). And, it is trying to develop the same melt holes. It is now showing codes P0171 and P2197. I believe those correspond to 'lean bank 1' and vacuum fault.

The best that I can figure is that the EGR valve is somehow stuck open and super heated exhaust gases are feeding back into the manifold - melting it. And a the excessive exhaust feedback is causing the car to register a vacuum failure.

Has anyone else heard of anything similar to this? Is the EGR line supposed to get so hot that it glows red (in the dark)?

 

i have the same issue please help! what causes this to happen???

 

I no longer have that car, but I did figure out what was causing it for me. And, that was a clogged catalytic converter.
It was forcing the exhaust back through the engine.

Hope that helps.