I replaced my fuel pumps several months ago with no known issues, but I didn't realize my gas level float/bobber was blocked by a fuel line and I ran out of gas with 1/4 tank showing. I never got the gas light, so the pig never went into protection mode to prevent air from getting in the lines. I think.... I put 4 gal in, and now it will start for only 10 sec, rev fine, but dies again like its in protection mode, but it may be air in the lines? Please! Any suggestions? I have durametric. I have no CEL's. No low fuel indicator. Guessing its still in limp mode or air in the lines. What do I do now?
Thanks for any input.

 

You can still have fault codes even without CEL. Check fault codes with your durametric. May give you a better idea what the problem is.

 

OK, I went to plug in my durametric and found my battery 100% dead. Key got stuck in ignition, but pop the little tab out, push the tiny button, and it releases. Anyway, I put it on my battery tender for 2 days, then my pig started like nothing ever happened, but my sunroof is now not functioning. Prolly a fuse. I have been driving it for many hours, no problems. I think I ran out of gas because my gauge is off....I never knew the tank has to be at least half full before you change the fuel pumps, so I read on rennlist. Must be because you need to pull all power so you don't blow up. Haha. I'm guessing the dead battery reset possible limp mode? Crazy cars. I have other Porsches and very minimal issues. This Cayenne is great, but difficult to figure out at times. I still have one wheel that rides slightly higher than the others. Even according to durametric, and goes up/down so I'm thinking the release valve is OK. The level control is working. Stumped on this still. Anyway, hope my recent ordeal can help someone else troubleshoot similar issues.