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5.8 running rough

T

talkwitdave

Member
Hi All,
My 351 ford is hesitating and occasionally backfiring when accelerating. Smooths out after a bit but happens again,usually after running at low speed for a while. I have new plugs,fresh gas,new fuel/water seperator.Any ideas? Thanks.
 
Condenser, Fouled carb, bad fuel hose, bad ground. I would try the condenser first. Put in new points and cap/rotor while y'r at it.
 
Dist shaft nice and tight or is there play in it. Points look like what ? They opening and closing good ? Maybe all you need to do is re-gap and or run a piece of sandpaper over the contacts. Cap contacts look like what, rotor contact?

That all good then timing maybe.
 
Thanks guys. I should have mentioned I have the Pertronix electronic conversion. I'll try some carb cleaner and check the distributor and ground.
 
Check your connections at the coil. I assume it was running on the Pertronix OK before this latest roughness. Check cap and rotor. Must be fuel. Wager you have sticky needle valve or fuel pump problem.
 
Yes it ran great on the Pertronix for the past 5 seasons.I hooked up a timing light and it's right on the mark at idle(600 rpm). Sprayed some cleaner down the carb and added some gas treatment as well. Carb inlet screen is clean. Cap and rotor look good.Service manual says if the fuel pump diaphragm was ruptured ther would be evidence of fuel in the transparent line next to the fuel line,(I don't see any.)I took it back out and got the same results;it ran fine at low speed but when I brought it up to cruise it stumbled and hesitated continuously with the rpms floating between 2900 and 3300.
Should I change the fuel pump?
Is it possible the spark is not advancing?
Thanks.
 
Sprayed some cleaner down the carb and added some gas treatment as well.

Absolutely ineffective. You have a choice here. Either take the carb apart and check the needle valve and float bowl or buy a new carb and install it. I would lean toward the new carb option given the age. Rebuilt carbs never run right in my experience.
Edelbrock 1409; electric choke 650 cfm. Drops right in.
 
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