99 venture sputters

Have 99 venture, the engine was running like new, it has 380000 km thats right and did run like new, now one morning it sputters when started like it is out of time or missing and wont idle. Sometimes it starts and idles perfectly for about 30 seconds and then sputters for lack of a better word. Could this symptom be the fuel pump.? When I push hard on the accelerator it sputters and will backfire and when I let up the engine will run great till it dies, will not idle.I was hoping maybe someone could help me out. Just want say this
is a great site!

if you give it gas and it sputters and bucks then backfires then you might crank it and it might run 90 mph no problems the next time do the bucking jerking backfiring these are symptoms of a hard dieing fuel pump. try pressure testing the pump.also how many miles on them plugs/wires? did the fuel gauge go wacky in the last couple of weeks? the fuel gauge somtimes goes crazy before the pump starts acting up.also don't let it backfire too much or it will concusion the tps,crank[backside of motor],and cam sensors. plus it will crack the plastic intake gaskets.when my f/pump went out the fuel gauge went to empty when the tank was full as i was running 80 on 4 lane. a couple weeks before it started the jumping,bucking,jerking, backfiring.had it scanned came up bad tps, crank, cam sensors . put all three in still bucked and backfired. hooked a pressure gauge in where the fuel filter goes and put long enough hose on it so i could watch the fuel pressure as i drove it. somtimes it would get down to 5 pounds then the bucking and jumping and backfiring would start. if it died the pressure would go down to 0 .the fuel filter is right below the sliding door driverside.the f/pump wouldn't stop running it just wasn't pumping.. i have seen some put the pressure gauge on the fuel rail bleeder but on 3.4 it hard to get too because its behind the powersteering pump. pump gonna run you around $320.00. let us know what you find. bet its the f/pump

Funny the exact symptoms happened to me today 2/6 which led me back to this site. Plus, my Service Engine Light was flashing and then steady, then flashing, and then steady.
I also have a 99 Venture that ran perfectly till today. It has 104,800 miles.

I took it to local mechanic whom I trust, and he said it needed tune up, but mainly new spark plug wires, that one of the wires was not conducting right.
That may be the cheaper thing for you to try first.

I really appreciate your responses. I went and bought a used fuel pump, took it home and the pump doest work, I will be getting my money back. so I will try another one and see what happens. maybe I should check the fuel pressure first before I go and change it out again for nothing. Let me know if it was the plugs and wires. again thank you everyone.

checked the fuel pump it has a pressure reading of 40 to 50 psi even when the van stutters and back fires . Van still starts well and runs for about 1 to 2 min and then starts to bacfire. no power, wont idle. Fuel pressure is constant.
Need help

have you had it scanned to see if any codes come up? see what codes are coming out. could be a sensor and could be bad plug wires .sensors should pop a code . bad plug wires or plugs will come as a misfire code.if you have an autozone around you they will scan it free

okay I checked plugs and wires, van started to run somewhat. I looked under the van at the exaust and saw that the catalylitic converter was glowing cherry red. removed converter (thought it might be pluged) but van still acting up. no change. Also no codes or engine light on.

okay I checked plugs and wires, van started to run somewhat. I looked under the van at the exaust and saw that the catalylitic converter was glowing cherry red. removed converter (thought it might be pluged) but van still acting up. no change. Also no codes or engine light on.

When my MAP sensor failed at around 100k miles, it started to not idle at all. If I kept it running with throttle, it wouldn't die, but anytime I took my foot off the pedal, it tried to stall. Often, I couldn't get it started at all. Changed the map sensor, problem gone. I never had it set a code when this happened.
With your converter so hot, it sounds like its running way, way rich. Map sensor could cause that. Just a guess, but its cheaper than the MAF sensor!