[taskrov]

That is what he thought after the first time the engine ran when the rebuilt was first done. He could not figure what to do next. I took it to dealer who messed with it, but also gave up saying all electronics checked out and there it some "other problem" with the enfgine. The rebuilder took it from the dealer, put back whatever the dealer left undone and the car fired right and ran for two days before developing the same backfire. So ECM was fine. Now it has exactly the same symphomps. So I doubt the ECM is bad. Those things seem quite roubust.