My mileage dropped from 17 to 13 this last week and i was looking to possible reasons.

1st the wiring for the O2 sensor was melted onto the cat. One wire was actually touching the cat. I repaired the wire. but i don't know if i should just replace the sensor. the burnt wire is the one on the connection with the O2 sensor. If i replace the sensor i have no burnt wires.
i am describing that poorly, but i think you get the idea

i checked for trouble codes today
12
37
17
55

I had the battery off a while back when the alternator went nuts and killed the truck.

37 is a code for the tranny, on the 95 if you didn't get the trailer package you didn't get a temp sensor, so it is always there as is my understanding.

17 is a code for too hot or too cold. never got this one before. temp gauge in seems to work fine. no idea? ????

55 is end of codes

I have a 180 degree tstat in the truck would that cause the code? or do i have another problem?

let me know

i liked my 17mpg

not liking the 13

 

I'd leave the o2 in there for now, see if the mileage comes back up. if not then swap it ou.

 

Also your too cold code may be coming from a faulty coolant temp sensor. If it thinks the engine is running too cold, which would explain your code 17 it will dump fuel into your engine in an attempt to warm it back up and that would explain your drop in mileage. I would check the wiring on your coolant temp sensor, if it checks out ok them replace the sensor. If that doesn't fix it I would look too the thermostat being stuck open.



[IMG]local://upfiles/20323/9DF2E9C9AF4D45ADA5A3F9546C9AB6C4.jpg[/IMG]

The picture here I took off of RM_Indy's website, it shows you where the coolant sensor is located. It will be behind your alternator.

 

the temp sensor, is that a different sensor then the one that runs the dash gauge? or are they the same sensor

 

there are two temp units one is the sensor for the engine(behind the water neck) and the one for the guage (behind the alt)

 

I checked in the service manual just to be sure before I posted. According to it there is one sensor for both. That suprised me because I know alot of cars have one for the PCM and one for the gauge. Granted the manual is the 2000 model year. Is it wrong?

Page 383 if anyone cares to have a look.

 

I looked and i can see 2 sensors,
one has 1 prong inside and the other has 2.
the thermostat is new but i guess it could go bad?

the one behind the alternator has one prong on it.
any ideas?

 

I forgot to mention in that PM.....check the grounds as well. You have codes that all rely on good grounds to operate properly.


Good luck.

 

will check the grounds.
i know that i should expect a code 12 because i had the battery off when the charging system went nuts. so i can expect that one.

 

hmm interesting i always seem to get the tranny code here and there have a 95 too, wow congrats on the 17 mpg! i average around 11 lol