1999 dodge grand caravan 3.3 stalls driving 20-30 mph

you meant CARAVAN? or grand caravan with
no engine told. size , 4 engines, 2.4 to 3.8L v6
so does not START and run
or does start and runs and stalls. (or runs for 3 seconds and stalls)
or stalls driving random. hot or cold engine,?
the starter motor always works perfect, spins GRRRRRRR and engine spins crank shaft fast or now, or starter is some times silent or just clicks.???????????
back fires to where? the rear car tail pipe end?
or to intake manifold (air cleaner side)>>>>>??????????
back firing to air cleaner , hits of gross timing of cam , burned intake valves.

tail pipe backfire can be what is called muffler explosions super load POP sounds, and is engine gross raw fuel lander there, mostly from leaking injector(s)
check engine lamp never glows, running or just before stall.
scan the PCM yet see stored DTC errors. (like CKP fails)

no engine told so hard to be more exact. above is generic.
ASE generic , gas engines,
if stalls driving can a fast right foot save the stall and if yes, do you still have full engine power.?

the 3.0L has a 2 cam timing belt(plus pump)
that fails easy, it slips and timing is lost !
and backfires every which way .
it is a 60k mile service point.
this 3.0L same belt runs water pump and you never want it to slip.bad belt too.
V6, 1 cam per head free running engine. (no bent valves) like the DOHC will do. 12v 6x2 heads no 24valve .

but no VIN or engine told.

Have catalytic converter checked

using a digital volt ohm meter test the throttle position sensor. if it has a dead spot at idle position it will stall. also if the throttle plate is dirty it can cause a stall at idle and all you have to do is clean it.

Could be a few things, Tune up, fuel filter, bad plugs, bad wires, dirty throttle body and crank shaft sensor.Good luck.

heres a few possibilitys. clean plate in throttle body. they get carbon around it and it will not run right. make sure air filter is clean, check fuel filter if need be. vacuum hoses for leaks. but clean throttle plate first. this may solve problem.

BREATHER HOSE FROM AIR PAN TO CARB

Maybe the Transmission Solenoid. The valves stick in them. They can not be cleaned. New trans solenoid is around $200

1 Inspect Carburetor Dirty and Improperly Functioning Carburetor. 2 Inspect Carburetor Incorrect Carburetor Adjustment. 3 Inspect Carburetor Worn, Faulty or Damaged Carburetor 1 Inspect Carburetor Worn, Faulty or Damaged Carburetor. 2 Inspect Mass Air Flow Sensor Damaged, Loose, or Faulty Mass Air Flow Sensor or Circuit

First I need to ask is it a 4 speed or a 3 speed transmission. If it's a 4 speed when driving down the road pull it from drive to third gear. You shpuld hear the engine speed up if it does not then that means you have on 4th gear and you will have to take it to a transmission shop. If it's a 3 speed then just count the shift points if all 3 gears are present then drive down the road and see if the van goes into tcc. When you mean the rpms are high how high are they.

try a new set of plugs, wires, and fuel filter. full loaded tune-up. air filter too.

May also be mass-airflow sensor if equipped. does it display a Check engine light?