[Tglowe88]

I have an 03 3500, 6 spd truck that I just put a motor in. Motor and ECM are from an 03 automatic. It runs and drives great, until you go full throttle. When you do, the truck falls on it's face and goes to idle for about 5 seconds. Then, throttle response comes back. I'm wondering if it is just an APPS problem, or is the ECM cutting fuel until it sees a successful downshift from the auto trans( that isn't there) the pedal sensor is the style that is mounted under the drivers side battery. Thanks in advance any ideas are appreciated

 

[nickg]

why not use the original ecm that came with the 6 speed, that would eliminate any ecm issues

my 03 has the apps up near the cp3, I thought the o4.5 and up had them under the battery

 

[Tglowe88]

Sorry forgot to add that the origional ECM was damaged by the rod that came out of the side of the block lol. The apps is under the battery in this truck

 

[tryNto]

I'm guessing the ECM issue you stated.

And my '03 also has the TPS under the Driver side Battery