another crappy mileage thread

[elwoodboll]

I have a 2001 Ex, 4 door, 4wd, 6 cyl, tow package with 91,000 miles. I've owned since new. Historically, I've gotten 17 - 18 mpg.

In August, in preparation for towing my car from SoCal to NorCal, I installed a second trans cooler in-line with the stock cooler. I installed it on the driver's side adjacent to the stock cooler. Trailer and car weighed in a bit under 5,000 lbs. but the trailer had a tire rack mounted up front that stuck up above the roofline of the Ex and acted like a big parachute. I also had the trans fluid and filter changed before the trip and I swapped in a new air filter. I've towed a bunch of times previously (different trailer) with no problems.

Anyway, the few weeks from when I installed the second cooler until my trip, the mileage was fine. But starting with the trip, the mileage has been horrible - probably in the 11 mpg range. The day I towed out of SoCal was August 26th. It was brutally hot that day so I waited until 9pm to head out but the thermometer going up the grapevine was still reading 105 - 108 degrees. The Ex ran like a champ on the trip with no issues other than poor mileage. But I attributed that to the trailer design (tire rack) as I've been able to average 15 mpg on previous tows.

What's going on? I've read a few other posts suggesting O2 sensors and plugs/wires. I would think bad plugs/wires would result in a gradual degradation of mileage. Do O2 sensors just stop working? Don't have any "check engine" lights showing. Any help/suggestions greatly appreciated.

BTW, this site was a great resource for me when reading up on aux cooler installs. Thanks to those who take the time to post how-to's and pics.

 

[waskly]

the bigger the drag the more fuel you will consume.

also weight has alot to do with it.

i

 

[imp]

What's going on? I've read a few other posts suggesting O2 sensors and plugs/wires. I would think bad plugs/wires would result in a gradual degradation of mileage. Do O2 sensors just stop working? Don't have any "check engine" lights showing. Any help/suggestions greatly appreciated.

It runs well. Suggests plugs/wires not causing poor fuel economy. Consider fuel. Has anything changed, like more locations adding ethanol, or more ethanol added? Have they quit use of MTBE? Oxygen-adding additives cut fuel economy, sometimes a lot. Are you using the higher-octane rated fuel? That will decrease fuel economy.

Torque converter clutch not engaging, increases fuel use. But, normally throws a trouble code. T.C.C. slipping, same thing. Got enough juice in the transmission? Could it be slipping somewhat, or functioning not quite up to par?

Check fuel pressure, under load, if possible. Low fuel pressure increases fuel use, as computer adjusts to maintain output.

Just some thoughts. Sorry I can't help more! imp