2012speed3 stuttering under load

Hi guys, I’m looking at buying a 2012 speed3 with 70k miles and a rebuilt title that is running extremely rough. My friend bought it from a auction and he tells me it appears to have a new long block, he has replaced hpfp, fuel pump in tank, coils, plugs, compression tested good. The car idles fine and can redline it in neutral, in gear moving it stutters/bucks/ whatever you can think of above 2k rpm in every gear. It does throw a cylinder 4 misfire. Where do I start at diagnosing this? Car idles amazing but under load it starts to do these problems. I’m thinking turbo or ecu? Could the car need tuned? Any help would be appreciated as I have never owned a Mazda. As I said any input is helpful. Thanks

 

Does it have any codes? Have you done a compression test? A cylinder leak down test? Gapped the plugs properly?

 

I would start with investigating the cylinder 4 missfire. Pull the plugs and check that they are gapped to 0.027

 

We have compression tested it twice and they came back at 180 across the board. I will pull the plugs and check them today.

 

Confirmed they are gapped to 0.027

 

Do you have any way of taking a log

 

I’m assuming you would need a tuner for that? If so, no I do not have a way to pull logs from it. What would you suggest I buy to be able to do that?