Ive had a bit of problems with my truck sputtering the last few days, almost to the point of dieing. My truck is a 1982 Ford F100 with a 302, and c6 tranny. Im not too sure on my carburetor, all i know is it is the stock carb. The sputtering started around the time I put some high octane gas (93) from Exxon. Last month I had fixed an oil leak by replacing the valve cover gaskets, and I know it still burns a little oil, ( as it is visible in the exhaust ). So i suppose it could possibly be carbon build up on my sparkplugs but was told it was unlikely. I also checked for vaccum leaks, and none but i did discover that the choke on my carb is electronic and does not work.

I have tried all i can think of to get rid of the sputtering, as of now I set the Idle up higher so it doesn't die constantly. Any suggestions would be greatly appreciated.

 

Does it idle good, but sputter going down the road? Does it go down the road ok, but sputter when pulling a hill(pressing the pedal down some). Or does it miss all the time?

 

It only sputters badly once i come to a complete stop after going at least 40 mph. But while it is moving it doesn't sputter at all.

 

You just did some work on it, I am suspicious you might have some emissions hoses in the wrong place. It almost sounds like the EGR valve is not closing properly when the engine comes back to idle. How many hoses do you have on the engine, and are they still hooked up, or plugged off?

 

I didnt remove any of the emission hoses, and all the ones where there are hoses no more are plugged off. Plus i checked, and they are still hooked up. Ill double check if one came loose.

 

It could also be the motor is starving for fuel. 40 mph then letting off the gas to come to a complete stop is a big change in the fuel needs for a motor, and vacuum varies pretty widely when going from a loaded condition (acceleration) to a no-load condition (no acceleration, coasting, slowing down).

I'd start by changing your fuel filter on the carburetor, then taking it for a drive and see how she does. Chances are, you've probably got trash in the gas tank, and if you ran the gas tank down low then filled it back up, you could've really messed yourself up by pulling all that trash into the carburetor and fuel filter. The first thing that usually happens is a light silt builds up, then the fuel filter catches the bigger particles, and the smaller particles that build up can clog up passages in the carburetor, the jets, the needle and seat, accelerator pump, etc. If changing the fuel filter doesn't fix it, you might have to pull the carburetor apart and clean it out, then put a new rebuild kit in it to make it like new again. If you have to do this though, it's paramount that you change the fuel filter. Better than changing the fuel filter is installing an inline filter into the fuel lines that would catch all of the trash. The filters on the carburetor just about couldn't strain out a boulder.

 

Ok, i checked my emission hoses again. And they are still attached/plugged off. Although i started the engine and checked the hoses while the engine was running i did hear a slight hiss when i reved the engine from the carburetor, i couldn't tell from exactly where but it seemed to come from either the Brake booster or back of the Carburetor. Perhaps one of my hoses has a hole in it, either way ill check it out in the morning. Ill update you all if I figure it out. And More advice is still appreciated.

 

I would go ahead and pull the carb off. In behind the carb is usually a large round thing with a vacuum line going to it. That's the EGR valve. I believe they had two different styles, one where the EGR is mounted directly to the intake manifold, and another where it mounts to the spacer underneath the carb.

Either way, I would pull the carb and check the gaskets and the gasket surfaces. The EGR gases over time can disintegrate the gaskets, and sometimes eat away at the metal surfaces, and this can cause it to run rough and have a vacuum leak.

If you don't want to pull the carb at first, look at the large round EGR valve, and see if there is a vacuum line hooked to it. It there is, disconnect it, put a screw in the hose, and take it for a test drive. If the EGR is open any at all during idle when you are coasting, it will cause the engine to run rough and try to stall. If this happens to help the problem, I suspect the hoses are backwards on the control valve for the EGR.

 

good thing is the rebuild kits for stock 2bbl motorcrafts aint 50 bucks no more walker took it over and its 15 bucks and change my 78 was doing the same before it got dismantled rebuilt the carb and deleted the EGR no more problems also if it is your brake horse your brakes would act funny as well just somthing to think about

 

Alright, today I took my carb apart, it was clean on all levels ( I had cleaned it thoroughly 6 months ago BTW ). I thought that since I had a problem with burning oil; maybe my spark plugs were carboned up or dirty. I was right, but even when I cleaned them the sputter persists. I adjusted the air mixture slightly and saw a small change. But listening closely at my exhaust i can hear very noticeable misfiring. And the misfiring seems to be the cause of the sputtering. Again, i have hit a dead end of my knowledge. ( The spark plugs and plug wires are only 6 months old )

 

So you are just trying to get a little miss-fire out of it while idling? If so, I would keep adjusting the mixture screws on the carb, there are two, one on each side under the front of the carb. Also, make sure sparkplug wire #7 and #8 are not side by side going to the sparkplugs. They can cross-fire because of the firing order of the 302. Move them on opposite sides of the wiring holders.