So I have a 2003 cayenne turbo S 4.5 was in my way to work was going over a bridge lost power and it just died on me. Would not restart got it tied home. So far I checked for spark on all four cylinder on the driver side (just cuz it was easier) tried removing #14 fuse and jusmped both fuel pumps with a wire. Fuel pumps seem to work just fine. What should I look into next?

 

Get a device (durametric/PIWIS) to read out the fault codes from engine. It is going to save you a lot of time.

 

I do have a code reader and the only code on there was for a faulty brake booster

 

What type of reader are you using ? Some generic code readers do not give correct definitions for the fault codes. I had this problem drawing codes on my Cayenne using a Autoboss V30 (Which is supposedly a very good machine). Google the fault code, maybe you will get a different definition.

That being said the brake booster code could indicate a vacuum problem, so check for a pipe that may have come off, this could cause starting issues.

 

I recently got the brake booster fault warning. A little digging on other sites led me to find out it's a pretty common issue. There is actually an electric vacuum pump for the brakes over on the passenger side by the washer fluid. The pipe coming off the bottom of it seems to be a common fault. I taped it up for now and the fault went away. The part is pretty cheap but I'm having a hard time seeing how to replace a vacuum line that goes from the passenger side behind the false firewall all the way over to the brake booster on the driver's side. I think they may have built the car around this line.

 

If you can get to both ends, just run some coolant hose (reinforced) in parallel.