Help again! No throttle response, then CEL. 2004 Base

[Beelzy]

So, after parking I start to back up and only get idle speed, no throttle response at all.
I limp to the side of the road at idle, then the CEL comes on and I see "Check Engine Drive to Shop"
Any clues if it could be something Iike a snapped throttle cable? No code reader yet, so I'm
asking for any advice before it goes to the shop, which I was hoping to avoid.

Many Thanks for any insight!

Update.....

Took car to dealer, they came up with these codes....
P-102 MAF Sensor
P-0121 Accelerator Potentiometer (usually in conjunction with P-1121 &P-1122)
P-1139 Throttle Position Sensor.

The local PORSCHE DEALER, checked the codes..
supposedly replaced the MAF sensor with a super pricey OEM one.
At first they said it ran but choppy throttle, they wanted time to check more deeply.
Then two days later they said the MAF didn't work, still dead throttle, and went right to the DME
being faulty. Overlooked completely the throttle position sensor. I told them no thanks picked up the car and low and behold, NO dead throttle! It drives but choppy like a bad Throttle Sensor!

To top it off, they left it totally empty of a 1/4 tank of fuel and only drove it a couple of miles.