Shakey at 3000rpm

What gives?

Runs good from idle to 3000, then shitty from 3000-4000, then ok after 4000....just started doin this today on me....

 

its sputtery...if i give it more gas it returns to normal but if i just accelerate normally it messes up...

 

just put a fuel filter in when I did the lines...

I have another AFM I can swap in and try....

 

changed afm....no difference in how it runs....it doesnt do it unless im driving, I can sit there in N and rev and it's fine all the way up to whatever...but when I'm driving it's fucked from 2500-4000 or so...

 

I duno it's hard to describe...it only does it under normal acceleration, not when you floor it, for some reason...

 

I'd think a bent rod would fuck it up under all circumstances, not just from 2500-4000 rpm's....but then again...I'm not a mechanic...

the guy I bought the engine off of (edward_h), he frequented the old forums and I believe he has an account here....never had any problems with the engine (so he said) and I've only put just over 100 kilometers on it....so...it better not have a bent rod

 

the mounts aren't the greatest but they're still intact....I don't think that's the problem...since it's fine at low and high rpm's....I took out the spark plugs and had a look at em today...they look pretty shitty and burnt, I'll try replacing those this week and see how she runs...