So I was working on my 04 tl earlier and had the battery unhooked for several hours. After I hooked the battery back up, it idled for at least 20 minutes while I was putting new coolant in it (drain and refill).

I took it for a drive and it feels like it has 1/2 the power it normally does.

This has happened before when I've done an ecu reset. What I don't get is how everyone says that resetting your ecu made such a difference but in my case it's the opposite?

it does eventually go back to normal after a few days and the power is restored.

it did the se thing after I replaced my 3rd cat and did an ecu reset.

What's the deal?

 

get flashpro and that will solve all your problems

To be honest not sure why your car feels slower. How was the weather? Maybe the car pulled timing because of knocking?

 

Many cars that have the battery disconnected can cause drive-ability problems until the ecu goes through a relearn process. Some are so bad that it may take a week before the system is back to normal.

I actually have an EZ RED computer memory saver that I always use when disconnecting the battery on any car. It retains drive-ability codes as well as the settings for radio, GPS, etc.

 

Today on my drive to work everything is back to normal. It does feel like the car pulls massive amounts of timing.

The weather shouldn't be a factor as it only does it after the ECU is reset.

I don't know, its so weird. And of course now that it has returned to normal it does drive much better after the ECU has been reset.