Pcm Clear/ Reset? How To?

[Raydar]

The background...

2005 5.3 Silverado. (T engine)

A couple of weeks ago, I replaced my knock sensors due to a "knock sensor 2, low voltage" code that I was seeing. (Water got in the "well" and corroded the sensor.) While I was in there, I decided to clean my throttle body, since it was pretty nasty looking.

 

After putting everything back together and reconnecting the battery, it runs good, but with a couple of issues.

 

First, my gas mileage is worse than it was with the bad knock sensor. I really expected an improvement. I also expected to feel the power restored that I had before the knock sensor went bad. It's not a slug, but it doesn't feel like I thought I remembered. I could be wrong on this point however.

 

Second, as I'm coming to a stop, the throttle doesn't seem to be closing quite enough. The engine seems to want to be fighting the brakes. This was really bad when I first put it back together, but it has improved significantly.

If I shift into neutral as I'm stopping, the RPMs will increase 50 RPM or so. As soon as I come to a complete stop, the idle settles in to a steady 550 RPM. (It occurs to me that this "pushing" might be where some of my fuel mileage is going.)

I'm speculating that, over time, the PCM learned what it needed to do to maintain the correct speed as the throttle body got increasingly dirty. Now that it's clean, it's getting too much air, and the PCM hasn't realized it yet.

 

What I'd like to do is reset the computer to "zero", as it was when it was new, and let it relearn everything. Disconnecting the battery has not proven to be effective.

 

I should mention that all my DTCs are gone. None active or stored. The readiness monitors are still "N", however. This truck seems to take days and days to achieve "readiness" after the battery has been disconnected or the codes cleared with the scanner.

 

Any help will be appreciated.