Mpg

[EarlR]

Re: Mpg

I just recently replaced my fuel pump and filter and ever since then i get like 15 MPG, and my last tank, i didn't get on it at all and got 14.8 MPG and this tank i got 12 MPG...it used to get 19-20MPG and I was wondering does anyone have any ideas of why I would be getting so bad of MPG now?

First, do you know it was getting 19-20 mpg right before you replaced the pump/filter? The problem could have started before you did the repairs, and you just hadn't noticed. I would go with the O2 sensor, as everyone else has mentioned, to start, since that will cause mpg to fall off in a hurry.

FWIW, in my '02 with the 5-speed I will generally get 26-27 mpg with strictly highway driving, and usually average 24 in mixed (normal) driving.

[cam98aro]

Re: Mpg

Yeah I would love to get one of those Scan Gauges, they look pretty cool. As far as watching the O2's, find out first what the specs are supposed to be, like voltages and switching speeds. Then watch the O2's on the scanner and see if they are working as they should be.

Even if an O2 is not covered under warranty, I would replace it anyway. They are not real expensive. But they are probably the main thing that tells your computer how to run the car. If one went bad, the other is probably not far behind.

13 mpg is pretty bad, I'm kinda surprised you aren't smelling almost raw gas from the exhaust.

its really great, i might be buying one soon.. and i agree, 12-14mph is horrible, im surprised the car would even run right without getting loaded up with fuel.. another thing to look for is a bunch of black soot around the exhaust pipe

also with that mpg,you would definitely see black smoke from the exhaust, unless you are totally beating on the car

FWIW, in my '02 with the 5-speed I will generally get 26-27 mpg with strictly highway driving, and usually average 24 in mixed (normal) driving.

thats amazing, i usually get around 17-20mpg with a bunch of "country" driving (a lot of turns, little stops about 35mph speed limits)

[EarlR]

Re: Mpg

thats amazing, i usually get around 17-20mpg with a bunch of "country" driving (a lot of turns, little stops about 35mph speed limits)

I didn't think it was all that unusual - wasn't there a mpg thread on here a while back? Maybe it was that other Camaro forum? I seem to recall that mid-20s wasn't unusual at all for the 3.8L. And trust me, I'm no miser when it comes to the loud pedal :D I'm a little surprised that in the year I've had the car I've only gotten one ticket. I will say though that I'm very fond of the cruise control - on the highway I will use it every chance I get. I think that accounts for a lot of the good mileage.

[cam98aro]

Re: Mpg

I didn't think it was all that unusual - wasn't there a mpg thread on here a while back? Maybe it was that other Camaro forum? I seem to recall that mid-20s wasn't unusual at all for the 3.8L. And trust me, I'm no miser when it comes to the loud pedal :D I'm a little surprised that in the year I've had the car I've only gotten one ticket. I will say though that I'm very fond of the cruise control - on the highway I will use it every chance I get. I think that accounts for a lot of the good mileage.

could be.. personally i feel that cruise hurts MPG (in manual cars anyways)

i usually can see the road ahead, so i know when to hit the gas to speed up a little to make to over a hill.. cruise does not, and waits till the last minute, then mashes the gas pedal to the floor

[whitdog54]

Re: Mpg

Ok so i hooked it up to a scanner today, it wa showing Bank1 and 2. I orignally thought bank 1 would be bad, but both sides were reading almost reading the same numbers.

I do beat on my car, but not that that much, and there isnt any black soot...I have no clue whats up, going to clean MAF, clean filter, buy an 02 sensor for drivers side and see if any of that helps.

[bigbrian442]

Re: Mpg

The mv for the O2's should be moving from around 900 (rich) to close to zero (lean) all the time. If the scanner reads O2 cross counts, some do some don't, that is how many time in one second the O2 mv cross the 14.7 threshold (about450mv). The cross counts should go up when your on the gas, but always be 1 or higher. If it is at zero for any length of time suspect that sensor to be getting lazy. If you can't see cross counts, The O2 mv should never stop jumping.

[whitdog54]

Re: Mpg

it was constantly going from 100s-900s, my friend said it was hitting 1000s

[bigbrian442]

Re: Mpg

Even at WOT with my AFR at 12.5:1 according to the wide band O2 mine never go over 980 mv. How fast are they changing?

[whitdog54]

Re: Mpg

Very very fast, I could barely read the numbers

IIRC my afr was 13:1