I am having some trouble with my truck after a MASS air kit conversion (see this thread: MASS Air conversion on a 92 F150 - Ford Truck Enthusiasts Forums) and I am wondering if it may be because of some vacuum lines I have that are not connected. The truck was running fine before I did this conversion but maybe the new system relies on these lines more than the old.

My truck is running really rough and will sometimes surge past 4000 RPM just after I start it. I am not pushing on the gas at all.

First, I have two vacuum lines that went to a canister (looked like a coffee can). I removed the canister (for space) and just connected the lines together. Not sure if this has something to do with how the engine is running.

Second, I have one vacuum line that I can see on the passenger side of the engine, it is a yellow (could be faded white) or gold colored line. It appears to wrap around the back of the engine and connect to what looks like a selonid to the left of the ignition coil. I don't ever remember what this was connected to but would like to reconnect it. Does anyone know where this goes?

Also, does anyone know what these lines are used for? I'd like to understand how they fit into this whole situation.

I tried interpreting the vacuum diagram that is on the inside of my hood but I wasn't able to make sense of it.

As far as I can tell, those are the only lines that are disconnected.

Thanks

 

The yellow vacuum lines are for the thermactor air & should run from the solenoid near the coil (TAD) to the air control valve (ACV) at the back of the engine. There should also be another line that goes from the solenoid back to a vacuum source (either the manifold or the vacuum reservoir). That's the black line on the vacuum diagram. The thermactor air system being disabled shouldn't cause the problem you're seeing, unless it's causing a vacuum leak. Also, eliminating the vacuum reservoir (aka coffee can) shouldn't mess you up either. Have you checked for vacuum leaks? Can you pull the codes to see what they say?