94 Chevy 6.5 Suburban. My driveway is an uphill incline. Burb won't start when I'm parked in the driveway. Will start if I'm parked level on the street. Any suggestions?

 

Back into the drive?

Had the same problem with our 95 Tahoe. It was the fuel lines under the intake, We also had a fuel tank leak and fuel line leak by the fuel tank

 

Woluld also say air getting into the fuel system.

 

backing in the driveway is what ive been doing but ill start looking for a leak

 

I would try locating a Fuel Filter manager and get Diesel/biodiesel compatible lines to replace what you have.
Just do them all at once. Maybe T your feed line to the IP with the IP return line, pump up to 5 lbs or so with diesel - I've used a lift pump with lines installed for each end. A couple of barbs and your good to go. Put the suction hose in a container of diesel fuel and then check for leaks. if you want to check for leaks.
You can check for leaks by just hot wiring your lift pump, running it and then after checking the front of the system, bypassing the Injection pump to the return line and checking that part of the system.
You should have some fuel dripping someplace.

Remember to put caps on the Injection pump barbs if you pull the lines off

 

Trouble is that between the LP and the fuel level in the tank the lines are under suction and air leaks inmuch easier than fuel can leak out.

Replace the IP fuel return line with clear diesel rated tubing and run the engine at idle with the truck safely parked and observe the new return line looking for bubbles.

Bubbles there indicate air in the fuel and that it is getting in between the fuel in the tank and the LP,that means that even the sending uit dip tube can have a hole in it above the fuel level and allow air entry.

Another source of air entery that causes hard starts is from leaking o-rings on the filter housing that seal up the fuel heater and water in fuel sensor and the filter itself.

They leak fuel out and air then enters causing very hard starts.

 

Ditto on the clear fuel line and the fuel filter o-ring would be the first place I would start as I have replaced them on both of the 6.5s that I have had