more questions
 

I've tried with the battery charger hooked up which should have more than enough juice to pass any diagnostic. But I'll check the battery voltage once I get my voltmeter home from work. As for the throttle position sensor replacement, has there been other failures? Should i replace the entire throttle body instead? I've been driving this thing all weekend and every time except once, failed P1502. Once I clear codes it runs great for that key cycle. One more question, is the throttle body easy to get to?
Thanks.

While performing the adaptation, keep cycling the key until you hear the motor on the Throttle Body engage (you should be able to hear the motor on the Throttle Body). I have read where this has taken a few turns of the key for some reason. Leave the key on for one minute, then turn the key off and remove from the ignition.

Pedros
 

as in pedrosgarage.com has an article on cleaning the throttle body which would help you locate it and tell you what the parts of it are. Anything chew any wires?

replace the throttle body??!!?
no way.
go here for a picture of the sensor.
http://www.theautopartsshop.com/auto+car-usa+parts/porsche+boxster+throttle-position-sensor.html

it is two bolts and a plug. follow the air intake tube from the air filter to the motor.
Where the plastic tube meets the motor is the location of the throttle.. look on the side of the throttle body to find the sensor. I would take it off and spray some electrical cleaner into it. Because it is a mechanical spring, it may just be gummed up.

Sorry for resurrecting a very old thread. However, thesis he exact same situation I'm in and wanted to know how this was resolved.

Did the ignition thing work?
Did the egas relearn?
Did cleaning the TPS sort it out?
Did you have to change the throttle body?