Gas Mileage is Gone to Hell...Who's to Blame?
 

Hey all,

As you may or may not know, I recently installed a set of OBX V2's on my Max. However, in the process my gas mileage has gone from 25.5 (that's combined highway and city) to about 19.8.

First things first, I cleaned the MAF earlier tonight. So we'll see how that helps, if any, in the morning. I realized that I'd recently re-oiled my filter, and figured maybe that was the culprit. Coupled with the fact that while inspecting my filter tonight, I found a small hole had been worn through it, so it looks like it's time for a new one.

Now for the questions. During the install, I extended the primary O2 sensors with some 14-gauge wire and heat-shrink crimps, and wrapped everything up snug in electrical tape. Also, the rear primary was damaged (the outer shell was bent slightly) during removal from the old manifold. Could either of these be responsible for a poor A/F ratio? Or is it possible that a loose O2 sensor could be causing my issue?

Both my O2 sensors looked pretty rough when I pulled them out, so I'm wondering if it'd just be in my best interest to replace them.

If it's worth noting, my car doesn't feel sluggish or unresponsive. It's running fine, no high or low idle, doesn't smell like it's running rich, or anything of the sort.

Also worth noting, I threw a P0123 code earlier tonight, something about TPS Circuit High Input? If anyone has some insight into that. :gotme: But I don't see that contributing to my bad gas mileage considering the SES light came on yesterday, and my mileage has been anything but good since the install a little under a week ago.

Oh, and for the record, I've not been heavy on the pedal. I was at first, but after seeing my MPG go to ****, I've been driving like a granny to see if it helps with the mileage at all. Any input would be greatly appreciated...

maybe a sensor prbl but I'm sure your foot is part of the prbl

[QUOTE]Oh, and for the record, I've not been heavy on the pedal. I was at first[QUOTE]


Same thing happend with me when I got mine installed,kept hitting the gas hard to test them out.....easy on the gas

I've been easy on the gas. :bawling: I even had the battery disconnected a few days ago, so the MPG gauge was reset to zero when I started back up. I've been driving slowly since. Still no good...

So are you using the trip computer to judge your gas mileage? We all know that it isn't completely accurate. Best way to measure MPG is drive till you're at less than a 1/4 tank, fill up, reset your trip meter, drive again, refill and divide the amount of miles you drove by the gallons you put in. Now, another factor could be that your tires are not properly inflated. Have you checked that recently? I wouldn't imagine that it would make THAT big of a difference, but it could be attributing to your reduced MPG.

When's the last time you checked mileage before the change? You know blended gas is like 10-30% less efficient? Are you burning the same gas you were before? Have you went to heavier wheels since? Lower PSI? Diameter?
Sounds like a sensor problem though.

Same size tires and PSI, they're on stock rims. Last time I checked out my mileage was right before I pulled it into the garage to pull things apart. My secondaries are just hanging out in my engine bay right now...I haven't had a chance to run an O2 sim yet. Any possibility that's the problem? I thought the secondaries only monitored catalytic activity.

I'll give that a shot. I've been doing mostly around town driving, and I know the Max is supposed to do between 18-20 MPG around town, so I'm going to take it out on the highway a few times and see how things go...