So I decided to take the battery (optima red top) out of my summer car and run it it my Audi over the winter - rather than let it waste away and trickle charge it all winter. Drove the car all day yesterday (300kms) and this morning for another 20kms.
The optima had been sitting for a bit and didn't have a charge in it... So I hooked it up, boosted the car with the battery I had been driving in it, and let it idle for a bit to try and charge it.
I decided to go for a drive to help things out...
Got on the road and the car stuttered bad... I wondered what was going on.
I pulled over and noticed that it would almost seem to cut out at 1500rpm. If you pressed past that point the engine seemed to be fine. I thought it maybe had something to do with the battery - it didn't seem to want to hold a charge at all. So I pulled it out and put the old one back in with the intent of returning the optima.
Now it's doing the same thing... Gutless, cuts out at about 1500rpm.
I took a video of what it does... Basically I am holding the gas down and revving the engine up, then releasing. And pulsating your seeing is from the car - not me.
If you stand on the gas hard enough it will push through the stall but there is a split second of a blip that you might be able to see on the video.
Anyone see anything like this before?

The only thing I really did was change the battery...

 

Well, the engine is fine today - The car sat all night and when I started it this morning everything was fine. Seems like it was a computer reset type of issue, but theres no way to tell for sure.

Chad

 

I'm having the same issue I originally bought the car as a project it wasn't running the tps was removed and all the vacuum lines were disconnected when I finally got it started it wouldn't idle over 1500 rpm well it would but only once in a great while.finally after replacing tps,and the ecu i have got it running but now my automatic transmission has no power its like its starting out in 3rd gear and the triptonics doesn't work. while driving I've down shifted from drive to 4th,3th,and2cd with no change.could it be the transmission modular?