Ok guys, i have an 83 f-250 with a 429 and everything is pretty much original. i have this problem recently: it used to idle rough and surge to the point of shaking the truck (with the brakes hammered) at stop lights...only the surging was really inconsistant. then the problem grew to where if i stomped it off the line it would stutter and half way die out for a second and then kick back in really hard, and then continue stuttering lightly for as long as i had the pedal down. i then put a different carb on it to see if it was the problem. it ran ok for a few minutes and then started running like it was about to run out of gas and then died. after awhile i was able to get it back to my house but it died many times on the way home. now its to the point that i cant even get it to stay started long enough to get it into gear ...nothing better than a few sputters. it has the symptoms of no fuel at the carb but i KNOW that i know that the only possible fuel problem could be too much pressure (is that possible?) im thinking it could possibly be the distributor, the ignition control module, or some bad wiring, but who knows. by the way, the carb that i took off, i put on another truck and it ran like a top so i know its not a carb problem. any thoughts?

(sorry that was so long)

 

erratic surging is commonly caused by a vacuum leak. Check all vacuum hoses for cracks, burn through, hardness/brittleness and looseness at attachment points. Also---make sure all vacuum hoses are attached. Make sure carb is securely attached to manifold.

EGR valve. This part can be tested with a Mighty Might vacuum sucking tool. The part is expensive so you don't want to replace it if it isn't broke. Make sure EGR valve gasket is not blown out!!!(big problem -- caused by warped surface)

Install a new fuel filter. (you can't tell visually if a fuel filter is good or not - varnish buildup )

If you have backfiring or exploding muffler problem replace the ignition control module -- especially if your truck uses the type of module that bolts unto the side of the distributor.
There is a difference in quality. Holley makes one available through Summit.

Check fuel delivery. Unhook fuel line from carb, stick the hose into an empty milk jug, have a friend crank over the engine, see if gas shoots into the jug. No sense replacing fuel pump if you have good fuel delivery.

Hope this helps.

A good mechanic checks the things that don't cost any money first. You don't want to get in the habit of replacing expensive parts that you have no idea if they are even bad.

 

 

Well, i fixed the problem, finally found the time and patience to go out and solve it through the process of elimination (thank God for donor trucks), it ended up being the distributor...i suppose the pickup that tells the module and coil when to spark was only partially working.