RX8Club.com - Stalling after decarb

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Stalling after decarb

I picked up an '04 with ~100,000 miles 2 months ago, and it seemed to drive well when I gave it a test drive; it also had an engine replacement at ~55,000 miles. Almost immediately, I've been having trouble with a real rough idle and seeming power loss after the car got warmed up. To troubleshoot these problems, I've done all of the following, in chronological order:

Replaced plugs, coils, and wires with OEM replacements.
Cleaned the MAF/ESS with electrical contact cleaner.
Replaced the entire SSV assembly with the upgraded one; the actuator was broken and tapping really loud.
Replaced the cat with a BHR midpipe.
Replaced the air filter and cleaned the throttle body tube. It had small pools of oil sitting between the grooves of the accordion tube.
Ran the decarb treatment by sucking seafoam through the intake nipples.

The last 2 steps I did at the same time.

After I decarbed and blew all the junk out the exhaust, my car won't even try to idle without stalling. I managed to get it out on the highway and drove for 20 miles, but it still stalls without even trying to idle when I got home. It seems to drive fairly well, though with no real noticeable improvement from before. I don't have any hot start issues, nor do I get any CELs.

I'm really not sure what to try now... what could be causing it to not idle, but yet seemingly run normal?

Check your plugs.
Did you unplug the battery at all?

I replaced the plugs 600 miles ago. Do you mean check if they're fouled, or check the connections?

I did unplug the battery prior to starting, and I reset the ESS position via "break stomping". Verified by the oil pressure gauge sweeping. I also reset the steering angle sensor.

Decarbing the engine with fresh plugs is not recommended.

Unplugging the battery resets the ecu. Your engine is likely trying to relearn the fuel trims, which will take approx 4+ drive cycles. This can cause poor idling.

Alright I'll keep that in mind, thank you.

Also, it's not that it's just poor idle; It doesn't even attempt it, the rpms just drop off and it stalls. I also took it out of gear on the highway and it stalled in the same fashion.

Edit: Also wanted to note, I disconnected the battery twice before for repairs and it never had this issue.