fuel issue? need quick help

[gold84gmc]

hello, i have an 84 gmc c2500 with 350. i am having problems with it. i did a search on the forums and found a post that had similar problems. driving home and started to go up a hill (and sometimes on flats) and the engine started to become bogged down and wanted to die, so i let off the gas and it was fine. i managed to get up the hill and pull off the road, then when i put it in neutral it ran fine and reved it up in neutral, and the rpms acted like it had a dead spot sort of. put it in gear and try driving and can only get up to about 25 mph before it starts to want to die. i recently replaced the fuel pump, fuel filter, rebuilt the carb, replaced one of the tanks/sending units. its my daily driver, so help would be greatly appreciated.

[VileZambonie]

Sounds like you have a kinked fuel line. Check the hoses at the top of the tank and all of the other obvious places it can happen.

[HAULIN IT]

 Anytime your looking for advise on something that others haven't seen or know ALL of the story, it helps to be specific of what you did when, before you had this problem occur. Did this problem start & you then changed all of the parts hoping to fix this or did you change all of these things "fixing up" the fuel system & now you have the problem or did you just do the sending unit last, kinked the hose on top of the tank, putting the tank back in & the second time you drove it you noticed this problem or is this a "new build" you have just started driving everyday?  A little more on the details may help pinpoint your problem more accurately, Keep us posted, Lorne   

[gold84gmc]

the truck was fine when we got it, i changed the fuel filter and we took the bed off because we wanted to change out one of the rusted tanks and we put the bed back on it seemed like it started doing it..not immediatly but after a little while, didnt see any kinks and we didnt touch the other tank but its doing with both tanks. and then a couple of months or so i rebuilt the carb hoping it would fix it, it fixed it for about a week then it started doing it again (i also found the old float had a hole in it so i replaced it with metal one) (it also dosnt make a difference as to what grade fuel i use) so i replaced the fuel pump and there was no change in how it ran. so im thinking some weird problem with the carb? (maybe jets? air bleeds fell out?) idk 

[VileZambonie]

Well if it's not a fuel delivery problem then I would pull the carburetor back off and pull it apart again.

[HAULIN IT]

I agree with Vile, It sounds like you are not getting enough fuel for the demand. Going up hills requires more fuel than an engine under no load (in neutral) & where you say "you lifted & it got better" that is also a fine symptom of not enough fuel (you let the fuel system catch up to the engine demand). If you can rig up a fuel pressure gauge on it (taped to the windshield wiper, ect) I think you will find it going to near nothing when it acts up because there is very little volume. The jets, ect. have no way to be that wrong without changing altitude greatly or having a highly modified engine at very near full throttle for a period of time. Is your tanks switching for sure? I would look around at the hoses by the front bed floor crossmember to see if something is pinched a little. If you have fuel pressure while it is acting up only then, I would move on to the carb looking for the problem. Just my two cents, Lorne

[gold84gmc]

ok so checked over everything, and replaced a couple of the rubber lines that connect onto the tank switching valve and it didnt run any different. a bunch of people have told me they think its the air bleeds in the carb causing the problem? what do you guys think? and does anyone have any pics or know where they are located? im hoping to tear it apart tomorow but i dont really have an idea of what they are.

[86 chevy silverado]

I would definitely get a fuel pressure gauge set up so you can observe pressure drops if any while driving, if you have good pressure I would chase the carb, if not you have a problem elsewhere, such as pump, kinked line etc.

[TexasRed]

Check your plug wires too. Maybe they're no good? Maybe pull a plug or two to see if they're fouled? When's the last time you had a tune up? I know it sounds like a fuel delivery problem but it could be a variety of things. Stock carburetor?

[gold84gmc]

there is no kinked lines. and the plugs and wires are new. havnt checked the plugs since i put them in tho. my automotive teacher said its possible it could be the wires in the distributor broke? and also it seems like my whole distributor sits crooked (like looking from the front, it kind of looks diagonal...just slightly) and yes it is the stock carb. but i drove the truck saterday and it was fine for about an hour and a half, then it started acting up and i was only able to go about 5mph up hills, and then i drove it again sunday and it acted normal...WTH?? haha

[VileZambonie]

Well you need to determine if it's fuel delivery. Hook up a fuel pressure gauge and tape it to the windshield as suggested. The distributor is in at an angle so don't worry about that. If it was a cylinder misfire it wouldn't be doing what you're discribing. Whatever your problem is is effecting all cylinders.