Engine cranks and tries to start but doesn't can you help me fix it?

Would you also advise changing the camshaft position sensor? (If this helps, it seems like I have a much better chance of starting the car if I first move the key to the Accessory Position.)

Ok, like many other posts ive read online, this car, usually after have driving it over 30 miles or has made a few trips it will sometimes not start up. It cranks very fast but no fire. It is in the 100's degrees temp where I live.

Ive tapped, cleaned and swapped around the relays for the fuel pump/eec relays, had someone listen in the trunk for fuel pump and it comes on. Hasnt had a tune up in awhile but I dont think that is an issue because when it runs it idles great, great pick up, ect.

Now we noticed last time we tried a few things that when we took a plug wire off, put a screw driver in it and put it close to various metal parts in the engine and it had no spark, now I dont know if modern day electronics prevent you from testing spark like the old days or not.

I was told it could be computer, but would a bad computer do it more often? I have tried to put it in (N) but still doesnt start there either. Checked for loose connections, none can be found. I have not yet takin it anywhere to have a code done yet.

I have a 1995 Lincoln Town Car with 158,000 miles on it. Every once-in-awhile it will refuse to start. It cranks over very good but won't start. Ford has $100.00 ed me to death so I tried a mechanic with a very good reputation. Still can't find a problem. When it's running no problem shows up on the computer. Today, it did it to me after a funeral that I attended. I don't know if it was coincidence, or not, But thinking that a relay might have stuck, I rapped on the relay box by the computer and it started up. I really don't know if it was coincidence or not because I never know when it's going to start.

This guide help me fix it

https://www.2carpros.com/articles/car-cranks-but-wont-start

My car wont start I had a fuel pump put in. But my car wont start still but I notice I have a fuel switch reset or cut on/off switch. But I also notice the wires are extremely bad could that be the reason why it wont start

Before you start changing a lot or parts we need to make sure fuel is the problem. You can do one of 2 things, use a pressure gauge om the service port, turn key on then off see if fuel is present. The back yard way is to have some one turn it over and spray a little starting fluid in the air intake, make sure if you do this to spray it after the mass air sensor. If it runs, then fuel is the problem. The cut off switch do not have a lot of trouble, you can check it by probing both sides and see if continuity is present, it is a closed switch that opens to break the connection. If the switch is good you might have a bad crank trigger. When you turn the key on the ecm will power the pump for a second then stop till you turn it over, then the crank trigger sends a signal to power the pump.
Might be more info than you need but hope it helps.

New fuel pump, new fuel filter, cleaned plugs. No fuel to injectors.