can someone please tell me whats missing here?

[Rangers n' Hoes]

my truck has been misfiring and I noticed this when I looked under the hood. cant find any loose cables or anything that looks like it fits. the exposed part (see picture) is sucking air. any ideas, guys? thanks

its a 1994 4.0 V6 OHV if that helps any

 

[kunar]

there should be a hose there or a cap, probably just a cap.

 

[Rangers n' Hoes]

i put a cap on it and that didn't seem to change anything. its still running pretty rough

 

[Rangers n' Hoes]

put a cap on and reset the battery and it seems to be running fine. but I have a hard time believing that's all it needed. but for now I suppose my problem is resolved

 

[Kowboy]

Scroll to the top of this page, click on the Tech Articles Tab, then click on Engine & Fuel Tech, then click on Vacuum and Exhaust. You should see different diagrams for different model Rangers. I think you want to then click on the 94 Ranger tab or possibly the 4.0 tab. See if this can help you find where the missing hose is. I did see a point where that many hoses came together. You will just need to follow up from there. Happy Hunting.

 

[Kowboy]

You may need to look at the 4.0 as well. That diagram show hoses going to:
1) FPRC, (fuel pressure regulator)
2) Climate control
3) EGR, (Vacuum regulator/EVR Solenoid)
4) Brake Booster

There may be one going to the Automatic Transmission

 

[Kowboy]

From your photos, it looks like someone has recently put plugs and ignition wires on your truck. I'd suggest it got knocked off accidentally during this work. The vacuum nipple is also very clean.

 

[SenorNoob]

My '92 engine has a cap there that blows off regularly. I've come to recognize when it blows and look under the truck for it.

 

[Mark_88]

On some engines, the 2.3 in particular, there is a vent tube from the valve cover to a similar inlet on the intake...that is to pull excess vapor from the crankcase in conjunction with the PCV...if you don't have such a hose on either VC then that may be what is missing...

The missing hose/cap also, essentially, sucks unmetered air into the engine and this would cause very rough running...sort of like a vacuum leak...without such a hose it creates excessive pressure under the pistons that retards performance. It can also allow oil vapor to be sucked into the intake causing the blue smoke.

I'd look for a valve cover opening that may have been capped or possibly the oil cap having a hose that maybe someone took off prior to your having the vehicle.

 

[4.0B2]

If a cap doesn't make it run better, you have vacuum leaks elsewhere. Mines just a cap there