Drop in MPG

For several months my 97 SL1 has gotten really bad MPG compared to what it
used to get: 35mpg+ vs 25mpg now.
I have changed the plugs, but not the wires and was wondering if there is
a sensor or sensors that could be causing this.
And are the sensors something that I could change out my self. Also,
would any codes show up that may point to bad MPG?
Thanks a bunch,
MR

 

Check to see if your temperature gauge is behaving erratically. I had a '94
SL2 that had a dramatic drop in gas mileage and it was because a sensor (I
believe) went bad. Someone help me out as I can't remember what it was, but
it was notorious for failing on the first generation Saturns and there were
hundreds of subject lines brought up about it...Anyway, this caused the car
to run at erratic temperatures. My MPG was about what your getting in the
winter, but would be higher in the summer....

Anyway, just a thought and I could be way off base here....

IYM

 

Its the Coolant Temperature Sensor you are thinking of.... It is fairly
cheap at the local auto parts store and is also very easy to replace too.
When the engine computer receives a low temperature (cold engine at start
up), it enriches the fuel mixture to run/idle better, but as it warms up, it
leans out the mixture. When these break, they tend to go open and report a
constantly cold engine causing more fuel to be used. If the gauge does not
go to the normal operating temperature, then this would be a good reason for
the lower MPG and for a higher idle speed at stop lights, etc. too.

Bob

 

Checked your tire pressures lately?

 

Oh yeah...right on.

 

Thanks. I'll check it out.MR

 

Try some better gas (higher octane) as in hot weather the PCM has to
retard spark a lot with 87 and that can destroy MPG too. Even detriot
using 93 octane during EPA MPG tests.

 

WOW thats amazing! A bandage fix that has NOTHING TO DO WITH HIS DROP IN
GAS MILEAGE! A typical "fix" from a bubba. Mask a problem, that you just
pulled out of your ass, with a fuel that has less btu's and cost more!
Just what one would expect from an idiot. So why should he pay more for
gas now when his car of 10 years is just NOW loosing mileage on regular?
I'm waiting to see what kind of BS you can come up with for this one.

Why didnt you change the plug wires? What plugs did you get?

 

The wires look good and do not arc at night, but may try that after I see
if the new coolant temp. sensor helps. Checking gas mileage the next few
days and cleaned the soot of the end of tail pipe.
I installed the equivalent of oem plugs.
MR

 

Yes there is a idiot here and it is you without doubt. Oil companies
loves guys like you that are addicted to 87 octane gas for high
compression engines and relie on knock sensor to mask it and reduce
efficency aqnd increase gas sales volumes. Also if you had half a
brain in your head you would know that with age, octane requirements
of a engine actually tends to increase for two reasons. One is that
carbon builds up in chamber raising effective CR and the other is oil
usuages tends to increase some and this lowers effective octane of
fuel mixture too. But, since you do not have a brain you do not know
this nor can you begin to understand that though 93 has a few less
BTU's in it, it also allows for a much more favorable timing curve in
a engine swith a knock sensor which places peak compustion pressure
and a time in crankshaft rotation cycle to extract more energy from
expanding gases from fuel burn which yeild more power and MPG too
rahter than retarding spark with 87 and having the illusion that all
is well and when MPG suffers spending a lot of time and money chasing
gremlins rather than buying better gas. Funny thing too is at todays
prices even 89 is only about 3 to 4% more and 93 is 6 to 7% more so a
..8 mpg increase would pay for 89 and a 1.6 MPG increase would pay for
93 but see simpletons like you do not think that way. You only think
how much it costs to fill up, you never consider fuel cost per mile.

 

Wow I love it he waste his time writing absolutely nothing of value
without paragraphs and without a coherent train of thought. (Or spell
check.)

Your insults suck. Why you bother with them is beyond me.

Right out of the gate his tinfoil conspiracy hat goes on.

If you had half a brain at all you would DECARBONIZE the engine but
thats to difficult for bubba's like yourself. Instead lets half ass it
and waste more money per gallon on a bandage fix.

The computer wont magically advance beyond its program you moron. If you
had any experience using a REAL scantool and had it hooked up on a
fraction of the cars I have you would see "0 Deg Retard" and "0 knock
count" on all of them using regular. If its not retarding the timing it
sure as hell isn't going to advance the timing you idiot.

Funny I often hear about loss in mpg using fuel rated higher than the
car requires. I guess you have a magic wand.

You're entire history of post have been nothing but "chasing gremlins".
So tell me what is the torque spec for 2000 Blazer's "Caliper Bracket to
Knuckle Mounting Bolt". You claim its not 133 lb ft... If its not then
what is it? Come on tell me! WHAT IS THE SPEC!
http://tinyurl.com/2j44zv

Find me some post by anyone that owns a S-series that claimed an
increase in gas mileage using higher octane gas with stats included...
Come on simpleton, find me some post!

-----------------------------------
Snojob Follies:
SBJ: Dumb brake question
http://tinyurl.com/2ya3wo

SBJ: Front wheel bearings-2000 Blazer??
http://tinyurl.com/2j44zv

 

Did you also check the resistance? Usually you need a misting bottle
with water to see them arc. Usually the plug wires on these go long
before the plugs themselves.

Tail pipe soot is a non factor but carbon build up in the engine is. If
the coolant temp sensor tip is brass it should be ok and was likely
replaced once but if its plastic then it should definitely be replaced
regardless.

 

The soot in the tailpipe seems to confirm that the engine is running very
rich. Although the OP never said if the temperature gauge was working
properly or not, I'd put my money that it wasn't and the culprit is a
defective Coolant Temperature Sensor.

Bob

 

I agree its a much better route to go than wasting ones money on fuel. A
persons fuel mileage doesnt take a 10 gallon dive in 7 months (after 10
years) over something as ridiculous as octane. Plenty of people getting
well over 30mpg on regular in the s-series in some pretty damn hot
climates.