jacetheace95

Hello, I have a 1986 f150 4.9 liter 6 cylinder pick up. The last few days the truck has been sputtering, stalling at random times, and running sluggish whenever giving gas. It just got exponentially worse. It is very loud now & the oil pressure is also low. Engine sounds like it is not getting the right amount of fuel. Just opened up the hood and noticed a broken piece under the carburetor, a hose with a metal adapter that connects under the carb, pictured here. Does anyone know what piece this is? I assume this is what is causing the issue. Thank you in advance!

McLovin

Looks to me like EGR (Exhaust Gas Recirculation) valve. Where does the other end of the hose go to?

Steve83

It's the upstream secondary air injection check valve, and it has no effect on how the engine runs, or the oil pressure.


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It's just a massive exhaust leak, adding to the filth on your engine. You should really try to clean it up - it'll make it easier to find its other problems, and easier to maintain later.


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The most-likely cause of the poor idle is the design of the 1-bbl carb; it's held on the intake by only 2 studs, so it rocks on them, crushing its thick gasket, resulting in vacuum leaks. Even when everything is running perfectly, the unequal-runner manifold causes cylinders 3 & 4 to run rich, and 1 & 6 to run lean. A leak at the base of the carb makes a bad situation worse. Read this caption:


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To guess about the oil pressure, I'd need a LOT more info about how the truck is built, and its maintenance & repair history:


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jacetheace95

The other end meets up with more exhaust valves. I believe it is the secondary air injection check valve as someone mentioned below.

jacetheace95

Thank you very much for the information, I will be looking through everything.