hesitation/stumble when pushing gas too much in cold weather

[gold84gmc]

i have an 84 gmc with a 350 with a q-jet carb...in cold weather and sometimes in warm weather if i push the gas too much the engine starts to hesitate or stutter and it doesnt want to go unless i let go of the gas some...but if i put it in neutral or park and rev it up its fine...does anyone know what could be causing this

[Blue 82]

Check your accellerator pump shot
You may not be getting enough at the right time

[gold84gmc]

i tried checking that and i can hear and smell the gas but i couldnt see any(i dont know if its becuase i didnt have a light to look in the carb)

[Unofficial]

I have the exact problem. It happens very often in the winter and only sometimes when it's warm out. I have a TBI though.

[choptop]

I think the problem may have to do with the cold engine. Everyone I had would do the same thing until the engine got up to operating temp. The intakes and carbs on these dont seem to atomize the fuel very well when its cold. I figure the tbi would have less trouble, but it does still have to go through the intake. I imagine the fuel condenses in the cold intake. It wont do it in neutral because there isnt much load on the engine. I am not sure of this, its just what I have always thought. Every bigblock I had would not hardly move until it was warn. The small blocks didnt seem as bad, but still did it.

[gold84gmc]

mine does it even when the engine is up to normal temp....it just does it everytime i drive it in cold weather and sometimes in warmer weather

[choptop]

Check your accellerator pump shot
You may not be getting enough at the right time

+2 check timing as well

[Unofficial]

mine does it even when the engine is up to normal temp....it just does it everytime i drive it in cold weather and sometimes in warmer weather

Again, we have the exact same problem. I'll be up to operating temperature and it will still do it. And just like you, it happens in warm weather, but not as often. Sometimes it will pop and sputter too. You wouldn't think it would do this because I have TBI though...

[gold84gmc]

i know the timing is off but if it was the timing causing this then wouldnt it do it everytime...not just in the cold and sometimes in the warmth

[Donut]

If your talking last weeks cold, I was hesitating to.

I wouldn't rule out the choke either.  Not fully opening or not functioning at all could cause this.  I just hooked mine back up for this same reason.

Could also be icing up on you.

[gold84gmc]

it did do it the worst last week but it does it a lot if its below maybe 40 degrees or so...and does it rarely when its warmer...and i tried holding my choke open while driving because i was thinking maybe the choke is closing but it stays fully open

[82TARDIS]

I know I'm a newbie here, but I was having a similar problem back in November with my '82 C10.  I finally found a vacuum line that had slipped off...put it back on, and problem was solved.  Of course, that was on a little 250, but your 350 probably has the same problems, only bigger 

[gold84gmc]

i looked for bad vacuum lines or ones that fell off and didnt find any....even thought the TRC (throttle return control) has 2 vacuum line connections on it and one of them broke off a while ago...i dont know if thats the problem or not

[Prong]

Do you have an open air cleaner? I've found those things are problematic for me in the cold(er) weather.

[gold84gmc]

what do you mean?...do i have the lid flipped upside down?....if thats what your asking then no i dont