@anesjehel what do you mean by "my heater core is also blocked so heater doesn’t work unless I unblock it"? All of this sounds like you are not getting enough air, or to much fuel. It sounds like your engine is burning to rich. When you change your engine, did you change the ECM or did you get it reprogramed. I would at minimum have your Subaru's OBD II scanned. See what codes are popping up. These may be an engine control module issue.
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@anesjehel what do you mean by "my heater core is also blocked so heater doesn’t work unless I unblock it"? All of this sounds like you are not getting enough air, or to much fuel. It sounds like your engine is burning to rich. When you changed your engine, did you change the ECM or did you get it reprogramed. I would at minimum have your Subaru's OBD II scanned. See what codes are popping up. This may be an engine control module issue. Let us know what exact model year your Impreza is and what engine it has
@anesjehel what do you mean by "my heater core is also blocked so heater doesn’t work unless I unblock it"? All of this sounds like you are not getting enough air, or to much fuel. It sounds like your engine is burning to rich. When you change your engine, did you change the ECM or did you get it reprogramed. I would at minimum have your Subaru's OBD II scanned. See what codes are popping up. These may be an engine control module issue.