Ashton_1012

I recently purchase a 1998 Mustang GT with the 4.6. When I bought it, it had a little bit of difficulty starting, and some hesitation while driving. I figured it was a fuel filter, so I swapped that out no problem. I no longer have hesitation, but it is difficult to start. I found that if I turn the key to the on position for a couple seconds two or three times it starts up just fine. The problem is usually worse when the engine is warm. Any ideas? I also changed the air filter, but have not yet changed the plugs.

school boy

My guess would be the fuel pump is getting weak. How fresh are the plugs/wires? Is the maf clean? Any codes?

Z28KLR

+1 on fuel pump. When you key on the fuel pump runs for a second to pressurize the system; there's a check valve on the pump that is there to hold that initial pressure until you start the engine and the fuel pump then runs steadily. Sounds like what you are experiencing is fuel pressure leakdown due to that check valve failing (the turning the key to "on" position multiple times to prime the system is generally a good indicator of this).