94 voyager 3.0 Huge gas consumption

1994 ply voyager 3.0 Used to get 18 mpg on the hi-way now is getting 7 mpg.
Took it to the zone to get obd 1 codes pulled none found.
Van has a slight miss at idle, no miss at hiway speeds, accelaration is smooth.
New plugs installed 4 k ago.
Smells like it is running rich at times, but not all times.
ran seafoam thru the tank, with no results at all.
Where should I be focusing my concerns ?
Help it is my Daily Driver :banghead:

Have you checked the fuel pressure regulator, make sure there is not any gas in the vacuum line.

Have you checked the fuel pressure regulator, make sure there is not any gas in the vacuum line.
Could you share with me where the fuel pressure regulator is located ? I assume it is in the tank or near the fuel rail, what exactly am I looking for ?

Here ia link that shows what the fuel pressure regulator looks like:

http://www.oreillyauto.com/site/c/detail/BOR0/23066.oap?year=1994&make=Dodge&model=Caravan&vi=1077689&pt=02494&ppt=C0024

Regulator should be close to the fuel rail

To get the codes on your vehicle:

turn the key from off/on, off/on, off/on within 5 seconds. The Check engine light will flash codes, EXAMPLE-- flash pause flash flash means code 12 battery disconnected recently. Report back codes.

Here ia link that shows what the fuel pressure regulator looks like:

http://www.oreillyauto.com/site/c/detail/BOR0/23066.oap?year=1994&make=Dodge&model=Caravan&vi=1077689&pt=02494&ppt=C0024

Regulator should be close to the fuel rail

To get the codes on your vehicle:

turn the key from off/on, off/on, off/on within 5 seconds. The Check engine light will flash codes, EXAMPLE-- flash pause flash flash means code 12 battery disconnected recently. Report back codes.

Whoa that is a spendy part, I will check the vacume line for fuel in a few hours when it warms up to 30 today. I did the off on off on off on 3 times within 5 secs and no codes shown, at the check engine light.

try the key dance again by doing on/off, on off, on. You should get cel flashing doe codes.

try the key dance again by doing on/off, on off, on. You should get cel flashing doe codes.
Nope not a code at all, by doing on/off, on / off, ON CEL only goes on then off then off then on then of then on no flashes whatso ever.
where is it that i pull the vacume line from the egr to the fuel regulator to see if there is fuel in the line ? or

Here ia link that will help you understand the key dance better along with the code meanings

https://www.allpar.com/neon/codes.html

private message also sent

another allpar link:

http://www.allpar.com/fix/codes/index.html

another allpar link:

http://www.allpar.com/fix/codes/index.html
Ok, my CEL light works When the key is turned to on / off. on/off on within 5 seconds But it does no flashing of codes at all.
So, I guess with no codes it will be trial and error as to what is really the issue here.

I assume that you are doing the key dance without attempting to start the engine. If there are not any codes it should at least give you a code of 55-5flashes pause 5 flashes. meaning end of codes. If you are not getting this code then it makes me think it may be a problem with the pcm. IS the CEL light on when the engine is running? I would also test the oxygen sensor.

Hopefully someone will chime in with some ideas.

It has been awhile since I have been around a 3.0, seems to me they have a distributor and timing belt, I am I correct?

When it is dark out open the hood up while engine is running and see if the spark plug wires are arcing or not, thisn will tell you if the wires are bad or not.

Disconnect the battery for 1 minute, reconnect, start the van and shut it off. Cycle the key again. You are leaving the key in "on/run" when watching the light correct? You should see a code 12 (flash, pause, flash, flash) If not, then as tempfixit said, the PCM is suspect. That said, it doesn't necessarily follow that the PCM is causing your MPG drop. It may be just the fault reporting circuit in the PCM is shot. I don't know why but some cars will not give you a code 55 but run great.

Do you have any test equipment like a multimeter, test light, fuel pressure gauge, compression gauge? This may come down to throwing parts at it. If you don't find something quick and easy are you prepared to spend bucks on a 16 year old van?

Disconnect the battery for 1 minute, reconnect, start the van and shut it off. Cycle the key again. You are leaving the key in "on/run" when watching the light correct? You should see a code 12 (flash, pause, flash, flash) If not, then as tempfixit said, the PCM is suspect. That said, it doesn't necessarily follow that the PCM is causing your MPG drop. It may be just the fault reporting circuit in the PCM is shot. I don't know why but some cars will not give you a code 55 but run great.

Do you have any test equipment like a multimeter, test light, fuel pressure gauge, compression gauge? This may come down to throwing parts at it. If you don't find something quick and easy are you prepared to spend bucks on a 16 year old van? Update, disconnected the battery for several minutes, on off on off on thing again, Again no codes not even code 12 or 55. So yes I will check under the hood tonight to see if I notice the wires arcing, and post back those results. Yes I do have a digital multi meter, and a fuel pressure gauge. Not really big on the ideal of dumping tons of moolah in the ol beast. How do you check the 02 sensor ?
Humn

oxy sensor, connect scanner to data link connector underhood near battery. go into data section of scanner and read oxy sensor voltage. you can also just disconnect oxy sensor and see if things run better. when oxy sensor dies, it pretty much always tells the computer that the engine is lean so the computer interprets that it needs more fuel and dumps way too much gas. also a great way to melt the cat cause back pressure which kills power and gas mileage

oxy sensor, connect scanner to data link connector underhood near battery. go into data section of scanner and read oxy sensor voltage. you can also just disconnect oxy sensor and see if things run better. when oxy sensor dies, it pretty much always tells the computer that the engine is lean so the computer interprets that it needs more fuel and dumps way too much gas. also a great way to melt the cat cause back pressure which kills power and gas mileage

A bad O2 will not cause something anywhere near as drastic this.

I also suspect major PCM issues. I'd be looking at maybe even mechanical issues with the engine such as low compression/bad valves/etc. Time for a real serious checkup of all major systems to rule them out before throwing parts at it.

my dodge shadow went from 32 to 14 all because of a bad oxygen sensor and no code or check engine light. quick test with a dvom showed .05v output. put in a new (used) sensor and I was right back to 32mpg. don't rule it out unless it's been tested to prove it's good.

try changing the air filter,that's what happened to my ford escape.After I changed air filter smooth idle and great gas milage.