engine missing when given gas

[Sachmo]

Alright guys. My dd is acting up on me. Stock 350 with a quadrajet. When pulling off the highway today my truck lacked power and would sputter when trying to accelerate. I pulled over and revved the motor to a sustained rpm around 3000 and it would miss randomly and pop on occasion. I checked for vacuum leaks and found none. Motot ran great prior to the end of this trip. Any iddeas what is going on fellas? This ones got me stumped

 

[Kapdin]

fuel filter or change the spark plugs and take a peek see if you find an odd ball.

 

[bucket]

What pops? The exhaust or out the intake? Does it still idle smooth?

 

[Sachmo]

plugs all looked okay. it has new wires on it and the cap and rotor looked okay as well. she idles just fine. could running on just the primary circuit of the carb cause this? the pop comes from the exhaust. maybe the distributor moved? i dont have a timing light to check it though

 

[belowaveragecustoms]

just curious if you found the problem and what it was. mine is doing the same sort of thing and was told that the vacuum advance could cause this sort of problem.

 

[Zaar]

hmmm? cant say ive had that many problems with a quadrajet they are pretty stout when rebuilt. check your choke. you may want to remove the carb to do a quick rebuild plus it's pretty easy for the most part. the metering rods in the carb do stick from time to time as well. when you get a chance try to get a timing light just to double check.

 

[MrMarty51]

Take a good long look at the top of the rotor,if it has any black sooty looking stuff on it then You have high resistance between it and the ground created at the sparking plugs.
Distributor cap,look it over reealllll gooood.sometime carbon arcing inside between the posts is almost undecteable.
Not always but most of the time a misfire,at lower rpms most usually indicates a secondary ignition problem,sometimes at higher rpms under load.

 

[Jims86]

Heres my $.02
I think you should check your float to make sure it has not failed...like deterioration or something, bad needle. Check the primary system...metering rods hanging up, trash in the passages.
Accellerator pum...could have a passage blocked, or am torn O ring preventing proper shot capacity. a kit may be a good idea. get some carbbdip, and compressed air an clean it really good.
Definately check the Ignition for crossfiring or bad cap and rotor. A failed vac advance does not cause a backfire in my exp....just really boggy.