I have a 1994 F150 with dual tanks 4x4 5.0 and I was having problems with stalling in reverse and having a push the gas pedal down to get it started so I clean the IAC valve and that fixed it but then it started idling at 1500 rpms I let it sit overnight and today I unplug both battery cables for about 20 minutes then when I started it up it had a miss and was idling at 1000 rpms with the check engine light so I turned it off and started it back up it was still idling high but didn't have the miss and the check engine light went off. While it was running I unplug the connector to the IAC valve and the RPM's dropped to about 600. So I plugged it back on and the RPMs went back up to a thousand. The guy before me put a k&n cold air intake on it so I took off the filter which was clogged up and when I took it off the rpms went up a little. So I'm guessing I have a bad IAC? I did the check engine light codes and couldn't read them but it is definitely throwing some codes. What should I do?

Also some vacuum hoses have broken off.

 

First off, replace vacuum hoses, that will cause major running problems.

Second, pull your codes.

Third, if you start the truck with the IAC unplugged (not unplugging it while running) and the way it idles changes drastically then you need to test the solenoid's resistance, should read 7-13ohms, if it reads anything different then it is for sure bad and should be replaced.

Follow these steps in order as doing anything before replacing the vacuum lines could be something that doesn't need to be done.

 

Do you know anywhere I could get a vacuum line diagram?

 

Or should I just follow and replace?

 

You don't need a diagram, I swapped all of mine out in 20-30 minutes. Just like changing plug wires. If using rubber/silicone tubing you will need either one 4-way vacuum tee or two 3-way tees. I overthought the process and did a couple hours of research, made diagrams, wrote out instructions, etc... BUT when I started the replacement that all went out the window and I just did them one at a time. There will be a couple sections that multiple lines are connected via routing clamps but just unplug one side of one line then route your new line to the other end, unplug and replace with new. One of the easiest things you can do to the truck that everyone tends to overthink.

FWIW I bought 22ft of 4mm hose from:
http://www.siliconeintakes.com/silic...686d47fdf65361

It is super thick walled silicone and will last forever, ended up with a foot or two left over but I wanted to be sure I had enough. It's $0.99/ft, which is a little more than the auto store's rubber line but I am planning on keeping this truck for the long haul so I went with the one time fix.