Miss at idle wont be coil packs
Could be too lean at idle (RB's Like to be quite rich at idle)
But if its coughing and farting could be a vacuum leak, dodgy MAF bad TPS etc
The thing with production engines you guys are missing is how many get thrown in the bin because they fail during testing.
Build 100 engines and there will be enough for 80 cars
Don't have that luxury with my pockets to build 5 motors and pick the best one