Hi. I'm brand new to AF, and this is my first post.

Me: Most of my life, I've known very little about cars, but I'm a recent college grad without a steady job yet, and becoming more car-dependent. I figured now was a good time to shed my ignorance and start taking responsibility for my automobile rather than paying through the nose for preventable repairs without knowing if I'm getting scammed. I'm also preparing to move across the US at the end of the month, hauling a small u-haul trailer. I've bought a Haynes repair manual, and been reading through the forums and other sites for a couple weeks now. I'm still quite a newbie, though.

My car: a '98 V6 Camry (non-CA). Been in the family since new, mine since last summer. I hit a deer going ~70mph last summer (no apparent serious problems), but otherwise accident-free. Has not been maintained as well as it should, I'm sure. Seems to have some electrical glitches, like intermittent brake light, radio occasionally cuts out, electric locks act funny when the driver's door is open...

Issue #1: the following fell off my car three months ago (first pic); I forgot about it for a while, until issue #2 came up. Today, the guy at AutoZone said it was a heat shield, and I probably couldn't find a replacement without replacing the whole catcon or exhaust system. He also said I could easily do without it provided I wasn't driving over lots of dry grass. I just wanted a sanity check on his advice from the AF community. Also, based on the pics of where it came off, is this a worrisome level of corrosion?
http://i534.photobucket.com/albums/ee342/uunter/smallcarpix07.jpghttp://i534.photobucket.com/albums/ee342/uunter/smallcarpix01.jpg
http://i534.photobucket.com/albums/ee342/uunter/smallcarpix02.jpghttp://i534.photobucket.com/albums/ee342/uunter/smallcarpix03.jpg

Issue #2: Three or four weeks ago, the Check Engine light came on. I had AZ read the codes: P0135 and P0155, which are the heater circuits for the bank 1, sensor 1, and bank 2, sensor 1 O2 sensors, respectively (that's the rear and front upstream sensors). It was shortly after this that I bought the Haynes manual and decided to take my car into my own hands. (In the intervening time, I have not had any driveability problems.) Haynes prescribes the following to check O2 sensor problems:
Check the heater resistance (should be 11-16 ohms cold)
Check the sensor voltage while car warms up (should be .1-.2V for first 2 min, then fluctuate between .1-.9V).

I followed the Haynes diagnostic procedures for the front upstream (bank 2, sensor 1) and the downstream (b1s2) sensor; both heaters and both sensors seemed to behave as they were supposed to. I tried to do the same for the rear upstream (b1s1) sensor, but couldn't access it easily enough (last pic below). I'm tempted to think that it's a higher-up electrical problem, especially given the other electrical glitches, but I don't know enough to be sure.
http://i534.photobucket.com/albums/ee342/uunter/smallcarpix05.jpghttp://i534.photobucket.com/albums/ee342/uunter/smallcarpix06.jpg
http://i534.photobucket.com/albums/ee342/uunter/smallcarpix04.jpg

So I have several questions: 1) Any suggestions on how to get to the rear upstream sensor? 2) Any ideas on what the problem might actually be? 3) Is this something I can ignore until after moving, since time is limited?

Thanks.

I applaud your use of twist-ties as test leads...waste not want not.

For Issue #1, ayup, it's just a heat shield for the catalytic converter, so nothing to worry about. I don't expect you to idle in tall, dry grass in a Camry, EVER, but you might be able to get a new cat under warranty depending on the terms...check your owner's manual. Some emissions-related equipment are warrantied up to ten years, you're right at that limit but can't hurt to ask. The corrosion build up is ugly but normal for somewhere south of the saltbelt. Replacement will require a hacksaw or cutting torch though...those bolts are frozen.

For Issue #2, I would try to access the sensor from underneath if possible. All it may be is some oxidation on the plug contacts...connect/disconnect a few times and blow out any debris with shop air or canned air. Use a dollop of dielectric grease around the connector gasket and have AZ clear your codes, then see if they show up again. If so, you can spring for a new sensor (~$80). Is it critical to the engine? No, it will still run, but the false reading will affect the engine's timing and probably cause you to suffer poor fuel economy.

If it were me, I'd get it fixed and have the car as healthy as possible for your cross-country drive while towing a trailer. Meaning oil change, transmission fluid change, coolant system check, brake check (especially when towing!), and A/C check. Towing can tax all these systems and in the dead of summer, your car will be working its hardest hauling you & your crap up & over those Rocky mountains.

Good luck...hope this helps!

Thanks for the quick reply. Regarding the trip prep: I've been checking everything I can with the limited tools and time that I have--I'll make another post about some of the issues I've come up with there--and making sure my fluids levels are correct, as well as tire pressure, etc.

Regarding O2 sensors: The last picture above, of the rear upstream connector, is already from underneath the vehicle. As you can see, I can barely reach the connector, let alone disconnect and fiddle with it. At this point, I'm running out of time before my trip, and I still need the car day-to-day, so I can't be trying to take it apart just to diagnose myself. I certainly want to fix the problem before too long, but at the moment it's a question of economics: will the decrease in fuel economy cost me more over the course of a coast-to-coast drive than it would to have a mechanic diagnose and fix it this week? Also, how long could that take? I leave on the 31st.

Well, you haven't said what kind of mileage you're getting now, so hard to guess how much the O2 glitch might be hurting you. If you got codes for both upstream sensors then I'd agree that the issue could be further up the electrical path if the supplied power is split to heat both sensors. An alternative, yet unlikely would be that the corrosion has either claimed one or both sensors or has prevented the sensors from properly grounding.

As far as getting to that rear upstream sensor...got any friends with long, skinny arms?

If your mpgs aren't far off from the window sticker (1-2 mpg), then I'd say you should be okay to hold off until you get to CA. But don't be surprised if your car isn't as peppy while going up the mountain passes...less air up there and a less-than-optimally tuned engine...a u-haul won't help either. Let us know how it goes! Good luck!

Well, I've been getting between 30 and 35 mpg driving to work and back every day over the summer--well over the EPA estimate for a 98 Camry--because I try to hypermile as much as possible, for environmental and financial reasons. For the trip, with a loaded car and trailer, over unfamiliar routes, I've budgeted money for gas assuming I'll get half that, and using $4.25/gal as a conservative estimate, which I think is a safe overestimate. At this point, I don't have time anyway, so I'll just deal with the sensor problem once I get to Cali. I just wonder what kind of mileage I could get with hypermiling AND a working sensor system.

Thanks for the feedback. I'll post again when I get it fixed.

I do not believe that gas mileage will be significantly higher once the problem is cleared....maybe 5%...depending on the extent of the hypermiling techniques you use. On the aside, I did start a thread abt a month ago for hypermiling tips & techniques, and yes I do employ a few of those myself (whoda thunk a '92 Cam would get 32 mpg!). I will say that I'd definitely err on the side of safety during your trip, especially with a packed trailer in tow as brakes can overheat easily in hilly terrain. Also check that enough of the trailer's weight is distributed to the hitch....eliminates "tail-wagging" and gives the rear tires weight on them for braking to be more effective. Good luck on your trip and have fun!

I do not believe that gas mileage will be significantly higher once the problem is cleared....maybe 5%...depending on the extent of the hypermiling techniques you use. On the aside, I did start a thread abt a month ago for hypermiling tips & techniques, and yes I do employ a few of those myself (whoda thunk a '92 Cam would get 32 mpg!). I will say that I'd definitely err on the side of safety during your trip, especially with a packed trailer in tow as brakes can overheat easily in hilly terrain. Also check that enough of the trailer's weight is distributed to the hitch....eliminates "tail-wagging" and gives the rear tires weight on them for braking to be more effective. Good luck on your trip and have fun!

Could you explain what hypermiling is. any chance you could post a link to your hypermiling thread. Thanks.:)

JOET/CAMRY

I made it to California! The Camry was not happy to haul the trailer--seems like the suspension is more worn than I realized--and I several times had to redistribute weight further back in the trailer to take the load off the rear axle. But it did the job with no serious problems. Whew!

It will be a while before I can get back to the sensor problem, but I'm with family now, and can use their cars for now. When I do get back to it, I'll post what I learn.

Could you explain what hypermiling is. any chance you could post a link to your hypermiling thread. Thanks.:)

JOET/CAMRY
Hypermiling is the collection of driving techniques intended to maximize fuel economy; that is, getting more miles than you're supposed to out of a given amount of gas. Here is jdmccright's thread: http://www.automotiveforums.com/vbulletin/t912865.html

There are a few others on the forums, too; just search 'hypermiling'. In the meantime, I can tell you some of the basics:

(DISCLAIMER: some hypermiling techniques, if taken to an extreme, are unsafe. Use good judgement and don't put fuel economy ahead of safety.)

-Keep tires inflated to the max recommended pressure, to minimize friction losses.
-Remove unnecessary cargo to reduce weight, and unused external accessories like roof racks to reduce drag.
-On the highway, cruise at speeds that balance engine efficiency against minimal air resistance (I think it's about 45-55 mph for most cars, but not certain; and it varies a lot from vehicle to vehicle and with driving conditions)
-Accelerate gently, and only as much as necessary to get to the next stop. The less you have to break, the less energy you lose.
-On downhills, shift to neutral and coast. I'm not sure this is effective with all cars, but I know it works with my Camry; the rpm drops, and I get more speed than if the engine is engaged. (Careful with this one, though--I always keep my hand on the shifter while in neutral, and if it's a long downhill, I'll shift back to drive for some of it to give my brakes a break.)
-And of course, keep your car in good shape.

There are many other techniques, but these are some of the simplest. Hope this helps. Save money and save the planet.

-On downhills, shift to neutral and coast. I'm not sure this is effective with all cars, but I know it works with my Camry; the rpm drops, and I get more speed than if the engine is engaged. (Careful with this one, though--I always keep my hand on the shifter while in neutral, and if it's a long downhill, I'll shift back to drive for some of it to give my brakes a break.)

To have your transmission in neutral is very dangerous: if god forbid something happens on the road, your car is out of control! Especialy on steep Californina downhills. When your foof is off the pedal, the car's computer under sertain conditions shuts the supply of gasoline. So this translates to ZERO gasoline spent vs some spent for idling.

Sam

Hence why I keep my hand on the shifter--it reminds me that I'm in neutral, and if there's any possibility of danger, I can instantly shift back to drive. Doing it this way is scarcely less safe than coasting in drive, and it DEFINITLY saves me fuel. Perhaps you're right that neutral uses gas faster than drive (though that's the first I've heard of it), but even so, I pick up much more speed from gravity in neutral than in drive, thereby putting more miles behind me for a given amount of engine on-time. Regardless of the reasons, though, I have gotten better gas mileage using this technique than without it.

Also, we should move this discussion to the existing hypermiling threads.

Glad to hear you made it to Cali. Camrys aren't really designed to tow any significant weight..I think they can tow 2000 pounds max? And max tonuge weight is 10% of that (200 lbs). Shifting too much weight away from the tongue results in an unstable configuration where the trailer hitch actually pulls up on the hitch ball, unweighting the rear wheels. This can reduce braking ability and can cause the trailer to "fishtail"...wag back and forth as you drive...obviously a very unstable condition. Again, glad you made it!

As for hypermiling, please direct all future posts on the subject to that thread:

http://www.automotiveforums.com/vbulletin/t912865.html