got my spare ECM flashed
 

I have a friend the works at the local dealership and he flashed my spare ECM with the stock tune and I can't believe how much better my car runs. No more rough idle, much better throttle response, no more HERKY JERKYS, and this thing runs a hell of a lot better than it ever did with the factory ECU. There has to be an updated flash that no one is talking about.

Is this a LS3?

Some interesting updates from tis2web...

12635479 00004935 New calibration to ensure proper operation of generic scan tools.
12634071 00008B67 New calibration to ensure proper vehicle speed is read by Onstar.
12635293 00007BC3 New calibration with enhanced misfire detection.
12635028 000071D8 New calibration with diagnostic enhancements for DTC P0461.

Yep.

So can we just go to the dealer and ask for them to update the software? It seems like there are updates that I should have...

How did you get a spare ECM and how much did it cost? Can GM detect that you change the ECM?

I used to work at the dealership so I just gave them my VIN# and ordered the ECM and I gave around 200.00 dollars for it. I got the spare so I could tune it and keep the original one stock for warranty.

that is too smart

Not for sure, but early LS3's were dynoing 355 to 360 rwhp. This would roughly apply to the first ten thousand cars. However, now after forty thousand and more cars the dyno results are consistently 370 plus. Same improvements for the L99's. It would seem to me that GM has tweeked the ECM tune over the past short history of our Camaros. It might help to have a recent reflash as pointed out in the earlier post. My 2 cents. :chevy:

This is very interesting info. Anyone in the know?

How hard is it to swap out the ECM?

They will be able to tell! The mileage won't match!

not just the milage.

GM keeps a file with the ECM serial number that is on a specific VIN.

So if you take it to a dealer and the car's VIN and ECM s/n don't match, the dealer will know something is up

I would assume that if you took it back to dealer it would have original vin# correct ecm and the spare would have the tune.