Intermittent Poor Acceleration power loss

I could use some advice on my 97 Legacy Outback. I had the engine completely overhauled, and it ran great. I took it on a road trip, the only issue was an intermittent high idle and EGR code. The valve seems to function. Then my cruise control quit..and so did the speedometer. No big deal, right? It’s throwing a speed sensor code. Next day the engine felt like it went to limp mode. (I don’t think it’s equipped with that) Again, intermittent. I figured out that when it goes low power I can stop, turn off the engine, and it resets! Off we go. I looked into the speed sensor and it looks like a well integrated wiring job. No connector. The fact that it resets when shut of and started again makes me think it’s a management issue like an ECU. Any advice? I don’t think the speed sensor Nor the EGR is related to the low power issue. I can manually trip the EGR and it doesn’t change.

Try to find another computer at the junkyard (ideally within 3 months of when your car was built.) In my experience, lots of random codes/symptoms like that tells me the ECU is dying. Also some cars didn't come with EGRs, so if you get a non EGR ECU then it won't even look for that data and then you can bypass it (if you wanted that is.)

If this follows on the engine out and in, check the three big connectors at the top of the engine to trans seam on the passenger side to see if they are tight. At this age they sometimes break during service and they may not latch anymore. If that helps you can try to figure out a ziptie way to hold them tight.

Fast forward on that acceleration problem. It went away and hasn’t come back! I have no idea.. I changed nothing and it’s working fine!