97 4runner trail build and catalytic

[endoscott]

Not sure if anyone is into desert trail runners but we have a 97 4runner Limited that we built for that, 185,000 miles, runs great, 2" lift, Bilsteins and OME springs, etc. Well my question is about exhaust systems. Recently got a CEL after driving over some rough roads and I am wondering if either muffler or cat is starting to disintegrate. It still runs fine but I just have a suspicion about exhaust system since its 24 years old. I didn't look too close yet but I didn't see any holes in muffler or anything. Maybe it's just an o2 sensor and maybe it's completely unrelated havent checked codes yet (will do this fall when we go back). But in general should I be thinking it's preventive maintenance to replace exhaust system header back at 185,000 and 24 years? Or on a Toyota maybe not.

 

[Wiredawg]

Unless there is something observable or specifically identified, I wouldn't replace anything associated with the exhaust system. I purchased an OBD II code reader a long time ago and recommend getting one so you can diagnose when out in the boonies.

Cheers, Ron

 

[endoscott]

It's coming...seems like an essential thing to have. These 3rd gen 4runners are pretty simple so I think I can do a lot of things myself. but the OBD II reader is essential.

I guess if muffler got plugged I could just saw it off real quick. Most likely cause would be hitting a big rock so that would be obvious.

Just not sure how long cats last on these, but I did a little research on aftermarket cats and it sounds like a GOOD one might last 5 years. The Toyota cats are expensive but clearly built to last. Pretty sure this rig will stay in the family anyway, so I don't mind fixing it right. So far I have only used actual Toyota parts and I think I will stick with that for everything.

 

[Topzide]

@endoscott, My guess would also be an O2 sensor. They often trip CEL without affecting the running condition. I'll agree that Toyota's are built to last! Worked with Toyota dealerships in the 80's - 90's. If I hadn't found the Ram trucks, I'd probably still be driving Toyota's! If you can deal with factory $'s, those parts will give the reliability that you've been used too! Enjoy that rig!

 

[endoscott]

I don't mind spending more $ if there is corresponding quality. I have never been disappointed with any Toyota parts I have bought. What good is a cheap Chinese starter from Autozone with a "lifetime" warranty that fails and strands you, then YOU have to supply the labor to fix it? Rather fix it once, fix it right.

 

[Ozymandias]

Toyota isn't the same anymore as 30-40 years ago. Today they are built as cheap as any other brand.

 

[AnonEd]

I'm not sure mileage is prime consideration for exhaust. I have 30 and 40-yr old cars (only 1 has O2 sensors) with 2xx,xxx miles and no exhaust issues, and 10-yr-old NE climate car which may drop it's exhaust from corrosion any day....but the cats work the same on both of them. Your O2 sensor may well be worn out (I got 90k-175k on my Japanese-brand OE), but as it happened after some rough roads I would also consider wiring leading to the sensors.

 

[endoscott]

Yeah I plan to carefully check all the harnesses and grounds when we go back.

 

[Robbie Antonosn]

If you have a smart phone, just get a OBD Wifi device, down load a good software(I use OBD Fusion) and read away(it is what I have my kids use, we have had 3rd gens for about 20 years, land cruisers for 25+ years). The original cats on the 3rd gen are typically good for about 250k miles give or take(I have seen a few into the 300K range). The cautions I have about these miles are if no Oil has been puking into the cats from an engine not working properly. I would also guess o2 sensor, but you really need to get a way to read the codes to know for sure. O2 sensors can can lead to overfueling or underfueling, effect fuel economy, and if over fueling, wash cylinder walls down and destroy engines. I believe that O2 sensors are under understood for a while.

As for the codes, most are for emissions(no EGR on the 3.4 engine), rest mostly are for Knock, TPS, water temp(different than the gauge), So not knowing the code and just go down the road can lead to issues.

As for the Cat falling apart. Has you power dropped, engine not responding to throttle response very well. then maybe the cat honeycomb is starting to plug up, but if you have not lost power, then I think you are ok. One thing to do, lay under the truck, have some one use the throttle and rev the engine, you listen close to the cat and see if you can hear a rattle, again, if no rattle, I do not think you have an issue with the cat.

A crazy Idea for you. Maybe learn a bit more about working on your specific rig, before taking it offroad(especially if you are by your self). I have helped my local(where ever I was living) Toyota club in the past for close to 20+ years. The crazy thing I keep seeing, people taking their rigs offroad with out knowing how to work on them, and not keeping spare parts and tools to work on your specific rig. I was happy to help broken down truck with my tools, spare parts and Knowledge during those times. But I did scratch my head seeing people stand by their trucks when they brake down, with no idea on what to do.

 

[endoscott]

Lots of good info, thanks for posting. Not afraid to work on it, but since these things rarely break down how am I gonna get that experience? I need to join up with a club for sure. I do carry the basic tools, good jacks and base, traction boards, heavy duty tow strap, etc.