Yeah, that's a junkyard engine. Nothing wrong with that if you can get it running well. Does it have the spin-on oil filter or a cartridge filter? The early cars got the cartridge (including the 2.3) while the later 2.0/2.5 got the spin-on.
Mazda did like to do random mid-cycle parts changes with these cars. I ran into this with my early build 2012 Mazda 3 all the time. It was built in May 2011, so it ended up with a lot of 2011 parts that were revised for the 2012-13 cars.
Definitely replace those solenoids and see how it behaves.
Just replaced the intake manifold solenoid that was bad. Started engine, still lumpy. As it warned up it got a little better. A few cycles of the engine off and on made the check engine light go out. It seems very lumpy just off idle, but beyond like 2500 rpms it seems to smooth out. Thoughts?
Could lumpy off idle be worn engine mounts. That is, when off the throttle is the engine excessively moving around in the engine bay? I'm literally just guessing. But, replacement engine done cheap still using the old mounts could result in sloppy mounts or not tight mounts.
Put your son behind the wheel and in the driveway and parked have him do a lot of blips of the throttle. As this happens does the engine seem to be moving too much?
