85 Monte Carlo 305 4 bbl

[Ace85]

I just put a new battery and alternator on, cars been sitting for a while, starts up fine. Idles good, when I give it gas it sputters, have to kind of pump the gas to get it going, is it a carburetor adjustment, fuel pump or filter? Has new spark plugs and wires and cap.

 

[Clone TIE Pilot]

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If an engine idles fine but stalls when accelerated or under load indicates a fuel supply issue. Using an analog dwell meter or a OBD1 scanner will help indicate such issues. Could be as simple as a clogged fuel filter. Very likely its a sticking float needle valve, especially if its a low quality needle.

Another possibility is a bad acceleration pump, cheap cup seals can swell when exposed to ethanol gas. Quick test is to manually push the acceleration pump plunger down and release. It should spring back up smoothly and quickly. It if sticks at any point its bad.

 

[MrSony]

See if you got strong fuel streams down the carb throat when you open the throttle.

 

[spongbob]

I suppose you have a quadrajet it like the previouse post say could be the accell pump some are adjustable that have 2 or 3 holes in the clevis arm on top .if so you have to knock the pin out with a rivet or small drill bit possibly .another thing is the check valves in the accel squirt circuit missing on ? Or the siphon ball valve ?is stuck it's most certainly in this circuit .Let alone sitting engine valve effects or valve lash event fouled plugs possible combine these all with loose back pressure you have a sure splutter recipe ?contributing ideas thanks with car motor off and air filter removed look inside the carb and push the protruding on of said accel pump sticking out of the too of the carb observers any fuel being sprayed as a result if you push it slowly you should see a small spray if it only sprays fuel when pushed fast ? try another accell pump I prefer leather ones but I suppose the blue cup ones are more available some of which are junk ..
Could be your problem will improve with a few days time and a couple ease it around the block trips ,some times a carburetor can dry out and have been know to improve with usage !...do not oil an accel pump ...
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