Need help finding out what a vacuum hose is. It broke and I drove for a short time with it disconnected and it seemed to seriously screw things up. (overheated)

1991 toyota 4runner
3.0 v6
Manual trans


Its coupled with a hose of the same size and they are both bigger then most of the other hoses.

 

Got another pic. Its the hose directly under the check valve and has a metal hose clamp on the end of it.

 

Don't know of a vacuum hose that would cause it to overheat.

 

X2 on no vacuum hose causing overheating.
Use this image to identify what hose you are referring to:

 

Thanks for the responses. Awesome diagram 93toyrunner2. I couldn't find anything like that online. The overheating must have been a separate issue. I will attempt to diagnose it further when I get off work later tonight.

 

I've had a series of unfortunate events. The overheating was due to a radiator hose coming off. No idea how it came off, it was the bottom hose, its in good condition.

Anyways the vacuum hose that cracked prior to that was the rear hose at AC idle up(4). I replaced it and it hesitated a bit for 1 day then went away, ran fine for about 2 days then it started to hesitate really bad. It idles fine at 600 rpm, when I give it gas (whether moving or in neutral) rpm's jerk up to about 2500 sit there for about 2-4 seconds then instantly jumps to about 5000.

I'm also getting awful gas mileage, although I am having to floor it to get anywhere so that's probably to be expected.

I replaced fuel, air filter to no help. About 2 months ago I replaced spark plugs, wires, rotor and cap.

I would greatly appreciate any idea's I'm at a bit of a loss. Thank you!

 

Check for codes.

 

Well my check engine light isn't on... It doesn't even come on when I first turn it to accessory (I get all the other lights for just a second) should that come on as well? Thinking I have a burned out bulb.

*edit* found a video of someone starting a 1991 4runner and saw a check engine light come on during start up, a light ive never seen since ive owned this car. I'll start on fixing that. Thanks for your responses.