hey guys,
we got the 2003 impala working, it drives, but it will go very slow, its slugish, it seems as if it has no power. it has new plugs and wires. 3 new fuel filters. fuel pump was tested its putting anywhere from 50-60 psi for the pressure, so the fuel pump is good. the p0404 has something to do withthe egr/ exhasut system i belive. i've been reading al lthe threads, and people have replaced the egr but it did not help. i unplugged the egr, but still no change, unpluged the maf and still no change. guys plz if you have any clue or idea, please let me know. im going crazy.

 

Clogged cat

 

man, you nailed it on the spot.
wow thanks alot. just got it replaced.
$160 bucks i guess thats a good deal eh?
and also i took it to the dealer to do a diagnostic, and they told me that the horrible crazy noise is coming fro mthe lifters. what can i do about that?

 

I thought that might of been it.
Lifters, do a seafoam treatment and see if that helps

 

what is the answer to the problem