My truck when warmed up will cut out as if it's either not getting enough fuel or air...I changed the smog (air) pump, the air pump diverter, the hoses running to all that...That helped some, it took longer for it to start cutting out.

When I'm driving down the road, no problems, but if I stop or slow up, it starts to cut out, or altogether dies, and on occassion backfire...

Also, there is a little tube about 9 inches long, and 1/8 in diameter hanging off the air filter housing (could this have something to do with it?)...I can't figure out where to hook this thing up.

Where is the fuel filter? I had it changed when the fuel pump was changed last spring (2007), and have only driven 5,000 miles since then, could this be clogged?

I hate to ask, but I have a rather large ski boat attached and people coming tomorrow...I can make it there and back no problem, but it will probably die along the way...

You guys have been so helpful the last few months. Thanks!

FUEL FILTER IS MOST LIKELY UNDER THE BED ON THE DRIVERS SIDE,IN LINE WITH THE GAS LINE

THAT HOSE IN PROBABLY A VACUME HOSE AND NEEDS TO BE ATTACHED.U MAY HAVE A VACUME LEAK WITH IT NOT CONNECTED.LOOK AT ANOTHER 350 TRUCK OF THAT YEAR ERA. GOOD LUCK

Could be the fuel pump its self, almost everytime I had a problem with my truck acting like that it was the fuel pump. It would run fine until I stopped. Does your truck hesitate once you take off again and then run fine once you're going? I swapped in an electric fuel pump on my 72 and never had anymore problems like that. But I was going through a fuel pump at least once a year, but I also had headers on it which I think increased the heat under hood and added to the problem.

It runs fine if I'm going and giving it a steady stream of fuel. If I let up, it begins to backfire and cutting out. However it doesn't act anything like it did when the fuel pump went out last year...

Does yours have TBI or carb? If its a carburetor it might be loading up, while at idle it is flooding the carb, but while driving its burning the fuel but may be running rich, if it was your fuel filter you would have problems driving more than at idle, b/c it would require more fuel at wot(wide open throttle) than at idle, you can take the filter off and blow through the inlet side and if you can blow through it fairly easy its fine.

Truck has a carb and it died last night after our last run from the lake.

What would happen is if I was giving it gas, everything was okay....I would 'ride' the brakes to keep the gas flowing to the engine...It wouldn't rock back and forth like it did the last time the fuel pump went out, so I don't think it's that....However, it did sound sort of like a backfire, but it's been 20 years or so since the last time I've heard one of these engines backfire, I can't be sure...

I can't get it to start at the moment....I'm going to change the PCV valve tomorrow and see if that helps...I'm also going to try to get one of the air pump check valves to come loose, but they are a bit rusted so....

My son had that problem with his ford. turned out, it was the fuel pump. for your truck, the pump may be in the fuel tank. some are. chech the book on that. although, im sure someone on here will know.
Most likely Not filter, someone already nailed that, and i agree, the more power you need, the more fuel it requires. if the filter was stopped-up, it would most likely shut-down under a load.
I always start with the simple-stuff first. Its just a process of elimination.

One last comment tho. more than likely, you have MORE than one fuel filter.
mrbrisket.

That little tube on your air filter housing could control a choke flap on your air filter.If its not hooked up it you could be choking it of air.And more than likely there is a vacuum port on the carburator that it hooks too.This will definitely be a vacuum leak.I would look real hard front back and sides and get that tube hooked up.If nothing else see if there is a flap in your air filter housing and make it stay open.

i'm guessing a vac leak to..might plug the open end of that hose and see what happens..

we want the final results..

Well I'm still trying to get that air pump check valve off...I've been soaking it in WD-40 every time I'm down at the lake...I believe it's an air issue and not the fuel pump...I just can't of how else to get that dang thing off...

There's a possibility that the low idle ports in the carb could be plugged/clogged.

Excuse my ignorance, but I've never touched a carb before yesterday when I pulled one off the new to me boat engine I got for the ski boat...Same engine is in the boat as in the truck...But which one is the low idle ports?

Sorry, did'nt want to confuse you but the idle ports are inside of the carb. It would have to be taken apart, remove the jets and blow air through those ports. It has a high and a low ports. Check to see that the body screws are tight. Around 8 screws that keep the top and lower parts together. They sometimes come loose and create a vacum leak.

Thank you for the information...I'll give that a shot...