My tpi 305 runs for 5 minutes then dies and wont restart why

might need new sparkplugs?

I saw what you replaced, didn't see any testing? What testing have you done? Make sure battery has a full charge?
When the problem is ongoing, have a helper crank it, while you check for spark at the plugs. If spark everywhere, use a gage and check proper fuel pressure. Also, check fuel injector pulse. Any applicable trouble codes?
If you have the spider fuel system, that system is noted for problems.

You may be having an intermittent failure with the fuel pressure regulator - checking the fuel pressure when the truck won't start may pinpoint this problem. If the pressure looks OK, this same problem can be caused by the ignition system as well (ignition coil or control module).

Hi Cherles, I'm glad to help!

I'm not there to diagnose it properly but here's a couple thing you can try! (1) When a vehicle sits for a long period of time the gas can go bad. I would make sure the gas is not full of moisture from sitting so long. (2) OH the old years when they had points. I would take the point out and see if they are burnt if they are replace them. Start here and see if this helps. Hope this helps and have an awesome day Cherles.

change the fuel filter and check the fuel pressure

does it have a b2960 security code set, i bet it does, it probably has a security problem and is going into fuel shut off, try replacing the ignition switch harness, this is 98% of the time the problem

Did you empty diesel out and just refill if so then you made a mistake which could have damaged fuel pumps

Diesels are suppose to be bled after refilling if have been run totally dry.

Change the spark plugs,they are worn out.

remove dog house locate test port and install guage should be 45-60 psi

i would check your ignition system. you would need a meter for this but look for broke or loose connections. if it was a fuel problem i dont think it would just start up after 20 minutes. or you might try your ignition switch. if its shorting or something then ya well it would cut your engine off real quick