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I have a 1980 Chevy Luv 4X4 that has been leaving me stranded on the side of the road. It would randomly shut off like it wasn't getting fuel. We replaced the fuel filter, fuel pump, and checked all the lines. It ran fine for about 3 weeks. Then it started acting up again. It starts bogging down like its not getting fuel then it just dies. I can hear the fuel pump running and it has fuel pressure. It seems to run fine until about 50 mph, anything over and it dies...I've asked a couple people and everyone has told me its probably the fuel pump...but what are the odds of two fuel pumps going bad? Any help would be much appreciated.

Sounds a lot like a fuel issue to me too. If you got a cheap aftermarket fuel pump it is possible it failed quickly. Not real likely but can't rule it out, I've had good parts fail quick. Pressure isn't everything in a pump, flow rate is important too. If you are testing the pressure it might be able to build up a good pressure but not suck up enough fuel to flow. Best to test both pressure and how much fuel it is putting out.

All of the times I've had this kind of fuel problem though the truck would generally idle fine, usually even run pretty well up to 30-50MPH then just stutter and falter until I backed out of the gas some. Very rarely did the truck just outright die. Makes me wonder if it could be something else. Points problems can mimic some of the same symptoms. If you haven't replaced them for a while, it is probably time.

I had a 79 that had sat for a long time. It would have random fuel delivery problems that came and went. It turned out to be a yellow jacket wasp had died in the fuel tank and gotten sucked up the fuel line. It was just small enough to fit through the pickup line and into the rubber line, but it would not fit through the inlet of the fuel filter. Since it never got into the filter I couldn't see the blockage. I'd blow air into the line and it would work fine for a while after that until the little guy would get pulled up against the filter inlet and block it off again. If you find you still have problems that point to fuel, it wouldn't hurt to drop the fuel tank and see what you find. Blow out all of the lines with an air compressor, and pull the fuel gauge sender to look at what is in the tank. In my case I had a few more dead bugs, and a 1/4 inch layer of chalk like crud on the tank bottom. I hosed it all out with the pressure washer at a carwash, got the tank dry, and all the mysterious problems went away.

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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)

MEPR: Man, my 4x4 makes all other LUVs look good

Sounds to me like your float in the carb needs to be adjusted. If I read that right and it runs good until about 50 mph then runs out of gas sounds like not enough gas in the bowl.
Hope that helps but what do I know. LOL

Do the fuse box fix. Until that is done you can get unexpected gremlins. The fuel pump is controlled by a relay that can be affected by electrical issues. Do a search.

Ok so I figured it out. It turns out when I went to smog my truck (a day before all of the issues) the tech had to test my gas cap. When he tested it he bent the metal ring under the gasket, so instead of being bent up it was bent down. Then the gas cap couldnt vent creating a vacuum, burning up my fuel pumps and making my truck die. Thanks for everyone's help!

LUV fuel tank caps don't vent if they are working right. The tank caps are supposed to seal, in fact you should get a slight rush of air when you break the seal because the fuel return line from the carb actually pressurizes the tank slightly. It won't hurt to have the tank cap vented & it's sometimes necessary when installing a Weber with no fuel return. The cap probably has to be sealed to pass emissions, however. If venting the cap cured your fuel starvation problem then you probably have a faulty fuel return.
I guess you could install a sealed cap just for emissions testing- whatever it takes to make it work.

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'78 Chevy LUV,1.9,4sp,headers,31's,SAS Dana 30,Dana 20,SOA rear w/Aussie Locker, rough body, bought new 12/4/78.
'87 Trooper,2.3,5sp,headers,31's,ball joint flip & spacer,Aussie Locker rear,Superwinch hubs,brush guard w/5.5K winch,more to come.