20 Most Recent 1991 Ford Econoline Questions & Answers

You aren't going to find vacuum diagrams on this site, you are going to have to find an old haynes manual on amazon or somewhere

I'm just guessing but I believe under the hood near the firewall

If you have an automatic transmission you need to check the neutral safety switch; if it's a manual check the clutch safety switch.

This will sound odd, but if the fuel filter hasn't been changed in a long time replace it and check that air filter isn't clogged up. If this isn't causing it you can try changing the fluid if it's been neglected and add TransX. If you need further help, I’m available over the phone at https://www.6ya.com/expert/oscar_403cc49e0f00cda7

Most pickup based motorhomes have 2 fuel tanks, you may have a tank selector valve that is electric or vacuum operated. Check underneath and follow the fuel lines from the tank to the front of the engine, somewhere in between you may find that the fuel hose goes to a valve that is used to switch between the 2 tanks ie: main fuel tank and auxillary fuel tank.

under right side of dash by heater plenum

Dave, Your question is incomplete! Are you reffering to the ECM, or the brain of your vehicle. Or are you wanting to know where to connect a code reader? The ECM is located on the Firewall approximately behind the battery. If you are trying to connect a code reader, there are connectors beside the battery, you have to fish around for them.

yes check that first but on some fords there is two filters that need to be replaced go to parts store tell them what you have to find out .

you must have the switch misadjusted the mounting holes should be slotted so you can adjust where the switch sits try loosening and moving it till it works properly and then tighten it down in that position