Help! Engine barely idles & cuts out after battery disconnect!!

[verTego]

Hi all
I recently disconnected my battery for about 30 seconds to clear the ECU's intake settings, but now the engine idles REALLY badly and dies after about 15 or 20 seconds... When it first fires up though, its perfectly smooth for about 3 or 4 seconds... its as if it suddenly loses 2 or 3 cylinders or something!

Background: yesterday I cleaned my MAF sensor (was a bit of black build-up on the wires/plate inside the sensor) and also removed the snorkel (accessed that thru the side grill) and afterwards the car ran well for a day... now this!

the ONLY code found with durametric is P1602 for a disconnected battery, and the CEL has not shown itself so far...

appreciate any help at all, thanks!