I have a 83 Z28 305 4BBL. When accelerating the engine surges, or bucks.
It sounds like it's backfiring out of the carb. Any suggestons or ideas would be appreciated

 

Most of the time, that's caused by inadequate fuel delivery.

Ignore people who say it's "timing" or "EGR". Especially the timing. Leave that alone, because it doesn't just up and change all by itself in the direction that will cause that. All you will accomplish by messing with it, is to create some more work for yourself, in the form of having to go back and UNdo whatever you DO to it once you fix the REAL problem.

The most likely culprit is the fuel filter, whcih is in the big nut where the fuel line goes into the carb. This is especially true if it runs OK for a few seconds when you give it gas, then starts it up; and is worst if you floor it.

Get a 5/8" tubing wrench from Sears or wherever, and a 1" open-end. DO NOT try to remove the fuel line without the right tool!!!! Or, you will be the next person to post here about "what do I do now I just twisted my fuel line". Use the 1" wrench to hold the big nut still while you loosen the fuel line nut. Might be wise to spray some PB Blaster on the threads and let it soak for a couple of days, spray more once or twice a day, to make it bust loose easier. Then once the fuel line is out, take off the big nut, and you'll see the filter in there.

 

OK - above you've been told to "ignore" me, but ....

every single time I've ever encountered a backfiring issue with a car it was ignition related and not fuel related.

If it were me, I'd do a basic tune up, plugs wires cap rotor - as well as the fuel filter (which should be done every 2 years anyway in my book).

 

LOL, now Im gonna stir up the soup a little here and tell you that both Sofakingdom and camaronewbie are correct. I have chased this problem on a few stubborn cars, certain it was fuel related, and found it to be faulty spark plug wires. Bummer is, in 3 cases, the wires visually inspected and tested fine. This can drive a tech nuts. Especially one like myself who insists on pinpointing the problem before I sell repairs.

This is how I've learned to handle it: Perform a thorough visual inspection of the engine. Check plug boots and porceleins for carbon tracking, pull the cap and check condition of the cap and rotor. Pull a plug and check it for wear. Feel the plug wires with your fingers. Are they stiff? A good way to check this is to hold one in your hand and see if it will stand straight when held in a horizontal position. A healthy wire should be limp. Check vacuum lines for cracking or splitting at the fittings. If during the visual inspection you find the tune up looks old, perform a full tune, as camaronewbie suggests, including the fuel filter, PCV valve, and all vacuum lines. BTW, I love sofakingdom's admonition on loosening the fuel filter housing. Too true. Vacuum lines that are supple can be skipped but generally replace them all. Especially the PCV hose as it will make a big vacuum leak.

If the problem persists, use the proper fittings(do not cut your fuel line) to install a low pressure fuel pressue gauge(0-15psi) in the line to the carb. Set it up so you can see it while you drive and verify at least 4psi of fuel pressure under hard acceleration, while the problem is occurring.

 

Thanks for all the responses, I replaced everything except the wires, which I just purchased today hoping this too is my culprit. I'll keep you all posted and again all is appreciated.