Prius 2001 (Gen 1) P3191 & P0300
My daughter (with some financial assistance from her parents) bought a 2001 Prius.
It's been giving her problems. Currently throwing P3191 and (pending) P0300 and driving slowly/weakly (I assume b/c the ICE is not starting).
Also it has a history of intermittent not starting when she first tries to fire it up, which has just gone away after she leaves it alone for a bit.
The first time she called AAA, they said her battery was dead (and bad) the jumped her and it started. When I checked the voltage after that, it was fine. Next time it didn't start, she did nothing, came back later in the day and it started fine.
The 12v battery is NOT a Toyota approved battery. Previous owner put in a normal Interstate battery. She took it to Interstate, and they tested the battery and said it was fine and the AAA guy "put the wrong numbers in his test equipment."
Fuel gauge is wonky, as I understand is pretty much normal, and she's thus run it out of gas twice. It currently has plenty of gas. She filled it yesterday.
We ran Techron fuel system cleaner through it when we bought it (a couple months back).
The VIN is low enough to be affected my both the ECU and fuel tank portions of TSB EG011-03 (it's JT2BK19UX1000XXXX). (But also old enough to be out of warranty).
Having read a bit, I am inclined to start by checking the plugs, inspecting the ignition coils and cleaning the throttle (especially having had a Camry subject to clogged IACV, and my wife's old 20R truck where the idle dropped due to dirty throttle).
Any suggestions after those first steps?
(In terms of what I am working with, I have a BT OBDII reader and Torque app, and do not own a fuel pressure gauge, but it might be worth picking one up if needed).
BTW, there are at least 4 Gen1 Priuses in my local pick your part junkyards, plus a couple of Gen2s (to the extent they share the same/compatible parts). So I can probably harvest parts like the ECU and Fuel Tank for relatively little money, although the work of removal (at least for the fuel tank) is not necessarily trivial.