Yep!! My buddy is chrysler mechanic and this fuel mileage problem has him baffled as well and any input is greatlly appreciated!! I will definately look into this tranny output sensor and I will keep everyone posted the best way I can so this can be solved one way or the other!!

 

Well we did a pressure test on the fuel pump and injectors and both after 5 mins both held their pressure at 58/56 psi respectifully. Lyle question that tranny speed sensor, wouldnt that give a code? and what impact would that have on mileage? just wondering!

 

If you had transmission problem,the ck engine lite would come on. But will give you P0700 code. Did your buddy look at the fuel trim with the DRB3?

 

Not a transmission problem, but may be (might be) sensors around transmission could miss few RPM's, just like some "lazy" O2 sensor didn't set code.

 

has the O2 after the cat been replaced as well?
a bad coolant temp sensor could cause this.

any chance your sucking in extra air from somewhere?

 

Hey guys!! Master Tech-> When I first got the van 2 months ago I did have a P0700. But the original battery gave up so it ended up erasing that code and hasnt come back on. Whats the parameters of the fuel trim? My Mac tool hand held gives me live data and I was watching the fuel trim. What controls that? I put a new O2 sensor in on friday and got another code yesterday mornin stating High voltage O2 bank 1 meaning the O2 is no good cuz everytime I cleared it, it came back so another new one coming tomorrow. The O2 after the cat, watching it on the hand held seems to be moving good, making its minimal adjustments. Watching the coolant temp after its warmed up runs between 192-203 degrees. I havent sprayed anything yet round the intake to check for small vacuum leaks yet, gonna do that tomorrow nite when we change the waterpump. Cant hear any loud vacuum leaks thou either. Thanx again guys for your ideas and time!! Cheers!!!

 

The fuel trim is control by the PCM, But it gets input readings from all the input sensors. And there are many. If they don't have a big plus reading or neg, The fuel trim should be okay. High voltage reading is a wiring problem, same as a low voltage reading. Check the o2 sensor connectors, when cold. Make sure you hear or feel the connectors locking.

 

Ok, I checked at an idle the fuel trim, its -2.35%. So I replaced that NEW O2 figuring it was bad!! No matter how many times I took the connection apart and reconnected it, I still got a high voltage reading!! So put another new one in and went to the store and the SEL came back on!!! This time it was heater error!! So double checked the connection and went for another drive. No SEL this time and avg 24 mpg at 45 mph on a short 15 min trip!! Gonna go for a longer trip and set the cruise at 65 mph and see what I get this time after supper!! Thanx everyone and hope this was the cause of my grief and hopefully some fellow dodge owners can get help this way!!

 

Well took the van for a longer spin. Set the cruise at 72mph(118 kph) on the 401 and got 26 mpg!!! Bout time!! Wife is happy now that she wont be using a $100 a wk to go back n forth to work 15 miles away!! Gonna change the O2 sensor after the cat also for ****s and giggles!!

 

Well the cheap NTK O2 sensors I think are garbage!! This was the second one in 2 weeks!! Started getting high voltage errors(P0132) and also heater code (P0032) so I broke down and went to the dealership and bought a Denso O2 sensor!! Hope this is the charm!?