I recently installed my KMiata E46 ZF 6Speed transmission swap kit and originally had an issue with the car starting up and running for a few seconds then dying. I have since fixed this issue by running a jumper ground from the old PPF grounding wire to the engine block but am now seeing a new issue.

When I am driving the car will randomly lose power and start to decel while in gear because the engine cuts off. This only lasts for 1-2 seconds and if I leave the car in gear it will start running fine again until this process repeats itself.

Attached is my tune file, a sample datalog and a screenshot from the datalog showing where this issue is located in the log.

I'm not sure if a damaged my MS fron trying to start the car without that ground in place or if this is still a grounding issue but if anyone is able to look at the file and see if they notice anything I'd appreciate it.

 

It looks like a faulty MAP sensor to me. When the issue happens, MAP plunges down to ~11kPa, hence the ECU cuts almost all fuel and the car bogs down. I don't any issue on any other sensors so I don't think it's a sensor ground - my original hypothesis as I was reading your post.

 

Dimitris, thanks for chiming in. I'll try changing it out and see if that fixes the issue.

 

UPDATE:
A friend had a new omni 3bar MAP laying around and I swapped it out with my old GM 3bar and couldn't replicate the issue at all. @Reverant Thanks again, you were spot on! Car is back to running flawlessly!

 

I didn't remember that you had an external 3bar sensor. I haven't had luck on my car with a GM 3bar either, it started reading lower MAP values (over time) until the car would no longer run.