Since I bought the truck, Ive always had some sort of fuel related issue. I cant let the tank get below a quarter otherwise it sucks air. First got it, fuel filter clogged. Later on after moving to NY (bought the truck in Virginia), Idling when its cold and wet. From the beginning when Im about halfway through when Im pushing the on the throttle, the throttle and engine shakes a little. Well the other night I was driving and then the truck stops. No noise from the engine, power steering is still working, i had to keep pumping on the throttle as if i have to get it started just to get it back running. Now i have had this happen to me before usually after a long trip. Usually when I drive over 80miles in one day. This time though i was commuting from work which is only 8miles away. When im coming home from work usually all the lights are green (i get out at 2am) so its a smooth drive. now the day after I commute to work and i noticed my engine is idling higher then normal. I shut off the truck and it sounds like it screamed at me along with a hissing sound. Just as a fyi, my heating and A/C do not work. my switch is broken and gotta get it replaced. the hissing sound i thought was normal. Also when i checked my oil, its black...i did the oil change not even 2000 miles ago. Since I moved to NY i switched the grade of gas because i noticed the truck runs ALOT better. I get 91 Ethanol free, grated here in NY its 3.20gal but to get better mileage and not as many fuel issues

1983 F150
4.9 straight 6, 300cu
4speed manual
168000 miles almost there

 

Hissing, rough running, high idle, no switch action. Sounds like a major vacuum leak. Check under the hood for vacuum connections like the power brakes, and trace down any pipe or tube coming out of the intake manifold.

You may be the victim of worn out or broken or crumbled parts or tubes, or the standard brittle plastic vacuum lines, or some PO half assed "desmog" effort.

Vacuum works the switchs, the brakes, maybe an input to ignition for vacuum advance, the evap system, and possibly something else I can't think of. (not the wipers though, thank goodness) It really sucks, but vacuum can be very useful as well, as long as it's controlled.

 

Yes, a major vacuum leak can cause problems... disconnect the vacuum line from the power brake booster and plug it; start the engine and see if the hissing is gone or not....

 

the hissing happens when i turn off the truck, sometimes it does it, sometimes it does not. its very random

 

Regardless of when it happens, disconnect the power brake booster and plug the line, then see if the hissing disappears or not. If it has, you've identified the culprit.

But it's awfully hard to hear a sound based on a typed description on the Internet; what we're thinking of as hissing and attributing to a vacuum leak may very well be compressed air in the cylinders leaking past the valves or rings or sumthin'.... but we do the best we can with what we have.... so it's up to you to diagnose it, we can only give you things to go check into....

 

I see what you did there

 

:%s/[i|I]t/she/g

 

How do you get no noise from the engine, but still have power steering?

 

yea i know late for a reply. I have noticed when its hot hot out or when the engine is over the halfway mark in the temp gauge it will make the hissing. One time a friend saw a small cloud come from the truck under the hood. As for the power steering, the engine does not fully stall out. its like the engine keeps running but not power comes from it. Not even pushing on the throttle give its power.

 

Do you regularly have to add coolant to the radiator or reservoir? Does your vehicle have a clutch type cooling fan?

 

nope, i dont have to add fluid. and clutch type cooling fan? sorry new to mechanics here not sure what you mean on the cooling fan part. if you mean the only way to cool my engine off its by having the clutch engaged then most likely yes because she HATES to idle. i have yet to overheat but usually i overheat (road rage) before i let it get like that

 

David is asking if you have one of these devices installed on your engine's water pump/fan junction:




Side view would look similar to this:

 

not sure, i havnt looked at my clutch and its one of the few things i wont touch personally because of my level of knowing how mechanics work

 

Well, get over it and go outside and look at it!

 

I think you guys are talking about two different clutches .