'08 xc70 Starts, won't run

[Faust]

Here is the deal. When cold, car starts and runs. When warm, it will start and run at idle for about 3 seconds then quit. Repeated tries will eventually get it to start and run. Prior to this the engine was running a bit erratically. I pulled codes and got a large number of codes referring to barometric pressure/manifold pressure. I also got codes for erratic misfire, each code listing a different cylinder 3,5 &6 as I recall. I am a carburetor and points guy, so I am a little mystified.

[jonesg]

do you hear the fuel pump prime at key on?
have you checked fuel pressure with the scanner.
your car should have the PEM pump controller on the tank or in the spare tire well.

when you say warm and cold are you talking engine temp or weather, just to be clear.

[DavidE7]

Your symptoms match a clogged fuel filter but could also be a bad fuel pump or partially kinked fuel line. I second checking the fuel pressure sensor with a gauge on the Schraeder valve.

Last weekend I helped a friend replace the right side fuel height sensor in his 2007 V70 2.5T. We thought it was a bad fuel pump. The tank showed it was half full on a DIM gauge. After pulling the fuel module and seeing the tank was completely empty and dry, I tested the resistance of the fuel height gauge using an ohm meter. It was then obvious that the gauge had dead spots and didn't measure empty every time when the float was down. I swapped out the gauge, we added 5 gallons of go juice and everything went back to normal. (Moral of this story is to try adding a few gallons of gas even if you are absolutely sure the tank isn't empty.)