Crank but Won't start

[michaelpat87]

Hello,

I have an older 99 Crown Vic. Lately it has had a hard time starting. It will crank but it has its days that it will start and others that it won't. I recently changed the starter becuase of some bad wiring inside it and I believe the Alternator was change 2 or 3 years ago. I know that the spark plugs and wires have never been changed but was not sure if that would cause it to not start or just misfire.

What do you think would be a cause for it not starting?

I appreciate you help.

[way2old]

Have you checked the fuel pressure? It should be around 40-42 psi when the key is turned to the on position. It should not drop more than 5 psi in 10 minutes. If it does, the fuel pump is getting weak. The plugs should be changed if they are original. My preference is OEM (Motorcraft). Good luck