OK, I'm still fighting the P0400 code. The P0431 code did go away with the spark plug anti-foulers. However, a new code appeared because I twisted some of the O2 wires upon reinstallation and messed them up. A new Bosch O2 sensor fixed all associated O2 codes. I'm no longer using the anti-foulers. No need for them.
I've replaced a number of solenoids as well as vacuum line and vacuum "T" connectors. Yet, the bloody P0400 still is with me.
Today, I made an order via Rock Auto for intake manifold gaskets and throttle body gaskets. I believe what I'll end up doing is removing the intake manifold and through the use of a few cans of brake cleaner and my air compressor - as well as various sizes of wiring, attempt to do my best at cleaning out the ports on the intake manifold with it off of my vehicle.
I'm getting down to the wire, as I have about 3 weeks left before I can get my emissions inspection done so I can renew the tags. If anything, I can clear up the P0400 code for long enough (25 miles or so) that I'll get through the emissions test and get another 2-year "breather" until the next emissions test.
It's not so much the P0400 - well, actually it is. Mainly, it's the idea of the check engine light being on. It frustrates the H E L L out of me. Given the efforts that I've applied to rid the car of the code, yet the check engine light seems to remind me daily that I've failed at some point or another.
