Chevy & GMC Vans

1999 Astro white cargo van with the v-6
Been having trouble for ever,maybe 3 months. Can't drive it now as it really runs bad after it warms up.
Not over heating.
It starts sometimes real fast then other times it takes for ever, turning over and over and over then kicking in.
The motor runs good until it warms up and then acts like it's running with water in the system, no water in there.
I have changed the CPS, TPS, the fuel pressure sensor, also the coil and the fuel filter.
Any ideas??
THANKS, Jerry

Welcome Jerry.

Pick the low hanging fruit first: engine basics:
replace air filter
inspect ignition system (spark plugs, distributor etc.)
measure fuel pressure.
Scan for diagnostic faults.

No warning lights.
New everything:
1999 Astro 230K
Fuel pressure ok.
Nobody can figure it out why it runs so bad.
Starts and idles ok, then as it warms it acts like it's running on water mixed in the fuel.
Cuts in and out. 
Not sure it's losing spark??
Good coil, all kinds of new sensors, new plugs, wire , cap, rotor, new filter, no water in the gas.

The question?? If I decided to get another older style distributor with the built in coil would that work or would the computer be a problem?
The throttle body would that work with a regular old style dist?
Would it work?  what problems would I run into?
Thanks, Jerry

yeah the computer controls the timing so I wouldn't mess with that.

jerryjerry05 wrote: ↑Wed Aug 17, 2022 7:44 pmas it warms it acts like it's running on water mixed in the fuel. Cuts in and out. 

I would suspect either open loop fuel delivery ...
take readings of MAF sensor and fuel trims

... or a plugged cat
take downstream HO2 sensor voltage readings
remove upstream sensor (to remove restriction)