Maybe a distributor issue???

[86project]

86 305 Chevy -

Runs good at start up and idle (other than startup smoke from leaky valves) - However, when driving it will start to cut out terribly to a point where it won't pull - it doesn't knock off and as soon as there is no load on the motor, it catches up.  Thought it was the carb, so I checked the filter, cleaned the carb to work smooth and tried to adjust it, but then it wouldn't start after???  So returned carb to old settings and it started right up but back to the old issue when driving.....ideas??? wrong carb adjustment??? I'm stumped unless it maybe electrical like distributor....And btw I am not a carb genius by any means...I know just enough to get into trouble - LOL

thanks ahead of time....

Brian

[VileZambonie]

Sounds like either fuel starvation or restricted exhaust. Check your fuel lines for kinks. Do you have a vacuum gauge?

[86project]

there is a kink (twist) in the fuel line right where it leads into the carb filter (been there since I got the truck)....I do not have a vac gauge but I can get one....I tested to see how much fuel is pumped out and it filled a cup rather quickly (thinking it may be the fuel pump also) but after talking to previous owner, it had been replaced about 2yrs ago....

do you think it could be a clogged cat?  from "burning" all that smoke from leaking valves?  any way to check that?

[Lt.Del]

does it seem to run hot?   I had a clogged cat on my 79 truck once and it would take a long time to get up to speed and i had to floor it to maintain 50mph while watching the temp guage go up. 
Too much back pressure through the exhaust...clogged cat.   Took a hammer and pounded the crap out of the cat to move the rusty suity junk around a bit and she ran good 'til i replaced it.

[86project]

not running hot that I have noticed but I can't drive it long enough to tell right now!.....however, it does get worse the farther I go.....in other words it is not as noticeable at first, but gets worse after the 1st mile or so...

[VileZambonie]

Fix your kinked line!

[86project]

guess that's a good place to start.....maybe this weekend....

[MITOYZ]

To check to see if your cat is plugged,drill an 1/8" hole in the down pipe before the cat, put a fitting in the hole,put vac/pressure gauge on it,start the truck let idle and check pressure, it should not be more than 2lbs of pressure if it is cat or exhaust plugged.take fitting out replace with bolt to close hole.

[VileZambonie]

If he has a vacuum gauge all he needs to do is connect it to manifold vacuum and nail the throttle preferably with a load on the engine. If the vacuum gauge stays at zero or extremely low that would indicate restricted exhaust.

[86project]

alright, fixed the kinked line.....still has the issue.....no vac gauge to test exhaust....but one additional piece of info.....it is running very rich even at idle.....could it actually be flooding?

[VileZambonie]

It COULD be many things. From the way you describe I would check for a restricted exhaust first.

[86project]

alright....will do....i'll track down a gauge....thanks for the advice guys....

[86project]

alright - only about 1.5 lbs pressure prior to the Cat......

what about vapor lock?  that line sits quite close to the motor.....? Stumped

[Blue 82]

Disconnect your fuel line at the carb
stick the fuel line in some sort of container, use an additional length of hose if necessary
crank the engine for 20 seconds to get 3 or 4 good spurts out
inspect the contents of the container
if you get any debris or water
repeat till clean
report back