[IMFrank]

For the first 10-20 minutes my engine runs very rough on wet mornings. It has never died on me, but coughs and sputters until it runs for a bit. I believe it's worse on cold wet mornings. It happens the most during winter of course. During the summer, it either doesn't happen at all or when it does, it's minimal. After reading some post, is that due to condensation in the distributor cap? One other thing that it does is, while driving at freeway speeds the engine has random misfires. It doesn't cut out for any length of time, I can just feel it instantaneously hit and miss. I notice it the most when I'm on a smooth freeway holding the same speed. Think it's the distributor or just the cap and rotor?

BTW-this is my 4th Astro cargo van and second AWD. I've never gotten better than the high 13 MPG. Now, I drive zero to five over the speed limit very aggressively, but how in the hell is it that I've seen some people posting they get 16-17 MPG?

 

[bryancraftyhands]

As for the condensation in distributor cap theory, the shoe fits.
Misfires, could be related, may also not be. Tune up due? Sensors ok? Any number of things possible.
MPG, Punching acceleration aggressively makes a world of difference in consumption. Most fuel is lost in first gear, picking up revs to gain speed. That's why Prius was designed to use electric up to 15mph.
There's a sweet spot in all vehicles that get very good torque and take off for the fuel and it's not with the pedal to the floor. Usually somewhere between 2k to 3500 rpms. Find that for whatever ride you are in and you will see and feel the difference.
Also, if all cargo, driving with ladders on top? Tools? Freight?

 

[tungtide]

Depending on the mileage you may consider a new distributor.

 

[MechBob]

If you parked it on a nice warm day,no rain and such, it rains overnight, and it acts up that morning, it ain't moisture in the cap. Moisture gets in there, when parked, not running, from a hot engine.

 

[MechBob]

I tend to take most fuel mileage claims with a grain of salt. Just too many variables.
The best I got in one of my AWD was--straight trad highway tires, traveling through Canada.
Close to 20. With 3 other people, and luggage. But remember, much lower speed limits there, and the fines for a out of country driver were huge. So usually drove 55-60, occasionally 65.

 

[ADDvanced]

I would put money on if you pull the distributor cap you'll see a bunch of corrosion.