Change the fuel filter and put some fuel injector cleaner in the tank. Hesitation could also be a "dead spot" in the Throttle Position Sensor (TPS).

Found one issue, there was no air filter in it, the pcv hose was detached, and the air box is royally screwed up. Bought a filter, new hose for the pcv and a couple gallons of 93 just for good measure. The dead spot is pretty severe accompanied by a slightly high idle. Thinking TPS and a dirty fuel filter. Also both donuts on the exhaust are toast. Gotta wait a week or two to get up some fundage for some diagnosis and repairs.

(1) check the TPS for a dead spot like Nate says
(2) trace all vacuum lines
(3) make sure your base timing is set right (pull the SPOUT and set it to 10 BTDC)
(4) pull the codes from the onboard computer

Severe exhaust leaks can also screw up the fuel mixture since the O2 sensor won't be getting an accurate reading. I'll warn you now that many of the late 80s Ford speed density fuel injection systems have been seriously mistreated by people who don't know how to work with them. Chances are you will need to spend some time fixing all the other "fixes" previous owners have done to the poor van.

Just rip all that crap off and get a four barrel intake and split header with a hei ignition

Another thing that will really help is to remove all the carbon build-up around the throttle plates. Also pull the the IAC motor (Idle Air Control), clean it and the air passages.

The fuel injection will give better performance, better fuel economy, and better emissions than a four barrel. Plus, it automatically compensates for changes in altitude. He already has dual exhaust manifolds because the motor is fuel injected. Swapping in a carburetor is a HUGE step back in every respect and would actually cost more and be more difficult than some troubleshooting and repairing of the fuel injection system already in place.

Bah ha ha! I wonder what YOUR lawnmower looks like


I will begin with what yall have given me to start with. Whats the easiest way to check the TPS for a dead spot? Ive chased as man vacuum lines as i can find so far, ill have to pull the doghouse to check all of them, thanks Ford for the handy vacuum diagram under the hood. If i had a torch i'd fix the donut gaskets myself. Maybe i'll start askin around. I can definitely hear a hissing under the hood when i shut it down so im guessing a pretty sever vacuum leak is somewhere in there.

I also pulled the cheat sheet from Google on how to pull the codes. Gonna tackle that tomorrow.

The easiest way to check the TPS is to get a volt-ohm meter and verify that the TPS has a signal output at all throttle opening ranges. Do a google search to find out how to check the volt output of the TPS. When you pull the doghouse, verify that the vacuum line is still hooked up to the fuel pressure regulator and you might as well go ahead and verify (a) what your fuel pressure is with the motor off and key on and what the pressure is with the motor running. You will need to buy or rent a hand-held fuel pressure gauge for a fuel injection system. It is worth it to install a dash vacuum gauge so you can watch what your engine vacuum is while you drive. At least get a hand-held gauge for diagnosis purposes.