Bad MPG, can anyone help me?

[RustBuket]

The joys of fuel injection..... /forums/images/graemlins/rotfl.gif

 

[dyeager535]

Yeah, people getting 13+ mpg towing, easy cold starts, no elevation change issues, more efficient power, hmm, sound like a lose lose setup to me. /forums/images/graemlins/rolleyes.gif

Since you have a scanner, does your ECM see correct vehicle speed?

 

[DesertDueler]

Yes my vehicle sees the correct MPH. And if this keeps acting up it will be time to put on my trusty q-jet. I use to get 16 mpg with the q-jet on my 86 k5 and it had 4.56s and 35s.

Dan

 

[dyeager535]

Park/neutral switch is operating correctly?

Running in closed loop?

 

[DesertDueler]

Runs in closed loop. I didnt check the P/N switch, but why would that make a difference? I know it switchs out of the P/N when I put it in gear so I assume it is working.

Dan

 

[dyeager535]

Yeah if p/n changes in the ECM, you are good.

Throws everything off if the vehicle thinks its not moving, or not under load, when it is.

You don't have a factory service manual do you? I don't have mine handy. I know they've got a section on poor economy. First thing they try and check is driver habits /forums/images/graemlins/smile.gif (not saying thats your problem of course)

 

[DesertDueler]

Like I mentioned in my first post I drove nice and easy. My truck never got over 65 mph while towing. I use to tow my boat with my burb with 35s and 3.42 and got 12 mpg. I also got 12 mpg when I put 38.5s and 4.56s on it when towing.

Dan

 

[jjlaughner]

NO help for ya for I got the 350 (with 100K+ miles on rebuilt motor), 700R4 rebuilt 2 years ago, 10 bolts and 3.08 with 32" tires and run 12-13MPG at 65MPH on the highway /forums/images/graemlins/smirk.gif