I have a dodge ramV8 extended van early 90's with a carborator, and it back fires. If I let it sit for a day or two, thentake it past 50mph, it will start to backfire. it will, loose energy, and speed. Then,I have to stop every few miles and start again because the van looses energy and I can't go any faster than 30mph to 35mph while the whole time it back fires. Does anybody have any insight as tohow I can fix this problem? Is it the carborator, distributor cap, plugs? What doesanybody think is the problem?
Thanks ifanyonecan help,
Bill

 

First thing I'd check is to see if the distributor cap is cracked or corroded.

 

My 1993 B250 van used to backfire. Got it from my dad.
Put new spark plug wires in it (MOPAR) Replace the wire plug by plug. The backfiring got worse.

Found out two wires were switched. The cheap wires I had on before probably caused all the electical things to be out of balance thus is just normally ran rough. (Plus sparks were arcing through this NAPA wire). With the MOPAR wires, van runs the best I have ever seen.

Get the firing order, place the wires in that order.
Plug 1 is usually drivers side front most.
Plug 8 is usually passenger side rear most.

ADDED:

You know, I just heard someone have this same problem on CarTalk this week. Klack and Klack suggested the timing chain is skipping or off track. You can use a timing gun to fugure this out. If the chain is off track, you wont even see the sync - according to them. Me, never done this.

Does this van have a timing chain?