Hi all. First I want to thank everyone that shares their knowledge and experience. It has helped me a lot when i've had problems come up.

Now I have another problem. Truck is a 74 250 390/auto tran. 2wd. When I am at a stop and then step on the gas (not hard) it will sometimes backfire then die. Then I can start it up and it'll run fine. The only other times it backfires is if I am doing about 40 or higher, take my foot off the gas, and let it coast down to around 33mph or so then step on the gas it'll backfire once and run fine. If I am at a dead stop and punch it it will also do some backfiring, usually killing it. Other than these times it runs fine. I've adjusted the carb (I know not correctly) and that does help if I set the idle higher. Is it possible my fuel pump is going bad? I was always told a mechanical fuel pump pretty much either works or doesn't.

If it is a possible pump problem should I test it or just replace it since they are pretty cheap anyways? If I should just replace it is there any particular brand I should or shouldn't buy? If I should test it do you know what the pressure should be, how hard is it to test and do most parts stores have the test for rent?

Thanks for any help.

P.S. I will be doing what torque king suggested in a different thread so I can adjst my mixtures correctly.

 

Sounds like your accelerator pump needs adjusting, see if it starts squirting as soon as the throttle moves, have to look inside the under the choke plate to see when you move the throttle. If it starts just after you move the throttle then when you set the idle up you are taking that first part of the stoke out of the equation and it works fine. there are different ways to set this on diff carbs but I do not know what one you have so I cannot help too much that way..

 

I agree, sounds like an accelerator pump problem. You also need to check your base ignition timing with a timing light. None of the adjustments you made have anything to do with the problem.