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

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!

go back over your work eg...look for a vacuum leak

Also look along that intake
 

and see if the black is oil...could you have a bad AOS?

What kind of air filter are you using?

thanks for replying...

will check my intake this afternoon. i really suspect something electrical tho as this happened immediately after the batt disconnect/reconnect... using stock intake with stock paper filter (recently serviced by porsche dealer).

I'm assuming you didn't disconnect the battery while the engine was running - if you did, you probably fried the output diodes in the alternator and if the battery voltage is already low, it can cause you problems......

Ok i finally found the problem... I removed the MAF sensor which i cleaned recently and found that even tho it was still nice and clean, it was coming apart slightly on one side (opposite side to the tiny glass diode thing), where theres a rectangular wax-sealed insert. when i reinserted it and left the wire harness unplugged, the engine ran beautifully. the unit looks as if it has slowly succumbed to age after 12 years and 104k kilometers. thanks again for your replies, hope this helps other boxster owners!