2.7 Bad Catalytic Converter?

Bout a month ago my check engine light came on p0420. I figured it wasn't a huge deal and I'm still driving it. I have 172k. Last Week I changed the valve cover, spark plug gaskets, and spark plugs while I was in there.

Truck was running great. Flash forward to last night, I was driving two hours back home, and my truck really seemed down on power. I averaging around 70mph and normally I can cruise in 5th gear and only downshift to 4th on a few big hills. Last night was like driving in a headwind! It was awful, even downshifting to 4th did not help much. I was on seemingly flat stretches of road and it was like I was driving into a 15 mph headwind. It was a calm evening, no wind.

I also noticed in the past few days when I rev to around 3100 rpms I hear this wild rattle/vibration that keeps going the higher I push the rpms.

I'm wondering if it's the catalyst breaking apart and clogging up my exhaust?

 

It could be, an exhaust backpressure test would need to be done to confirm it or if you tap on the converter and can hear it rattling inside.

 

My cat was replaced under recall. I don’t know if the recall included 08 but you might want to check with your dealer. Good luck

 

I believe it was for 2010+ trucks.
But the symptoms OP gives, sure do sound like what Toyota says can happen in the event of a failed converter.

 

Sure sounds like a clogged cat

 

Wow, as a 2TRFE owner the "only 15mph headwind" and downshifting would make me think those 4 cylinders must be bored out or really chooching. Jokes aside, does sound like she might be plugged. Hold up a piece of paper to your tail pipe, should blow on it a "normal" amount which isn't a great test unless you know bad cats. Same for sticking your foot over the tail pipe to listen and feel for change. But you can use a laser temp gun to see the temp on the pipe before, on, and after the cat. If after the cat is IIRC 30 degrees hotter, you're into plugged zone. Should be ehaust temp pre cat, cat will be hot, after cat should be a good 10-15 degrees cooler. This is all shade tree diagnostics.

 

Surely an 08 is way past recall if there was one?

 

I do need to take the heat shield off and tap on it. see if it rattles.

Anyone run without the shield? mine rattles around on a regular basis its super annoying I didnt know if there would be heat issues running without it.

I'll be honest it really probably only takes a 7 or 8mph headwind and I'm downshifting, thats pretty normal lol. But the other night it just felt like a dog on the highway. in town its not noticeable, still accelerates normally.

Definitely doing the temp test. I know that on idle exhaust flows normal as far as I can tell. getting up there in rpm ranges, flow may be more questionable.

 

All seems normal for a 2.7.


A fun way to check for a clogged cat is to pull the upstream O2 sensor, if performance returns then the cat is clogged, no change then your problem is elsewere.

 

Heh this sounds like it would be loud. Would this not cause some other performance issue?

 

Ya it is loud, but the difference is very noticeable if you do a hard pull from a stop. When I did it my truck didn't even throw a code. Just do a hard pull to like 20 mph then remove the O2 sense and do it again, the difference should be very obvious if the cat is clogged, not much change and the cat isn't clogged.

 

Recalls don't end.

Service campaigns and things like that do. My '13 was replaced on a service campaign.

 

Haha yeah, I would swing into the dealer to see if your cat was recalled then you can just pawn off work on someone else, my 2011 was recalled and they replaced the cat. And as others said, recalls change, my 2011 when I got it didn't have a frame recall, 6 months later it did. As far as the heat shield goes, you can rip it off and it won't matter. Just don't park on tall grass, which you shouldn't be doing in the first place anyways. That's more or less the only reason it's there. This would be emissions illegal, but if you were to have a truck that was strictly for off road use, there are "test pipes" and a few resistors will make a post cat o2 emulator to keep the CEL off. I've never had a shady exhaust shop replace a bad cat with a pipe, that's very illegal for them to do. I forgot what it cost to diagnose, I only had cash on me.

 

I tried this immediately after turning the truck off and with the heat shield still around the cat so probably not the best test but…

From before to middle to after it was like 310-415-340

what do you reckon?

 

I forgot to mention that test should be done at full temp not cold, so I'm not sure if it was or wasn't but I'm guessing it was ran for some time. The temp pre-cat should not be more than 20-30 degrees IIRC. Which either or, looks like you're hitting that point if your engine was at full temp. At min, if it was a car that rolled into the shop, I would start to be more confident it's probably a cat on the way out.

As someone else mentioned, you can just unbolt it before the cat, will be loud as hell, but if it drives better after that, that's good enough for me to call it a plugged cat.

edit: the pre-cat temp, should not be more than 20-30 degrees hotter than post cat.

Edit 2: might as well just google it. Close enough. https://metertestlab.co.uk/how-to-test-catalytic-converter-with-infrared-thermometer/

Edit 3: I'm also very dyslexic. So... I'm very very wrong here. I just remember temps have to be off some degrees. Otherway around apparently. I quit being an acual mechanic years ago. Sorry for the fuck up on my end.

 

Haha you're good, I'm trying to open that link but it's not working for me.

 

Air, fuel, spark, bang, exhust. Operating under the assumtion the cat is ok unless you unbolted it just for a "lets see what happens" diagnostic. Maybe it's in the front. Code doesn't 100% mean it's the cat, fuel conditions could trigger that just as well. Could be anything from an air filter with 100k miles on it, sensor issues, too many to blindly guess. Do you have or could get a scan tool or techstream etc tool, and see things like AFR, fuel trim, etc, live data? If you haven't done a visual inspection of the intake and air filter, just a free waste of 10 min to verify that's ok. Without seeing it, kinda getting window webMD territory where too many easy things can all cause the same-ish issues. On a cold start, does it start harder and rougher than typical? Could indicate FPR issues. With the same or maye not as bad, but a semi rough always present idle, I'd look at crank ventilation. That shouldn't I feel dog you down noticeably much but have owned a 2.7... doesn't take a lot to lose power lol. I'm still shooting in the dark here. Just reasonable enough things to check before cutting a check.

 

air filter is fine, checked it pretty recently. I have an ultra gauge, what metrics should I plug in and analyze? I would also need to know what numbers are good and bad

 

Long term fuel trim https://www.tacomaworld.com/threads/1gr-fe-long-term-fuel-trim-ranges.752994/

MAF Flow rate, which I don't have the computer I need to find what that should be for your engine so I'm hoping someone else knows since I didn't see it come up on a search. Same for how advanced/retarded the timing is and what numbers those should be. If no one has those numbers I can look them up later on tonight.

Oh that's right you're a 2tr-fe. I specifically searched for 1gr-fe lemme see if I can find it

Not seeing it on a quick google. I gotta jet, but if you can find the specs for the long term fuel trim, maf air rate, and timing, for the 2tr-fe then check what the specs should be against what you have. Otherwise I can look it up later tonight on my other computer I don't have with me now.

 

I had this issue myself about a year ago. I had already had my cat replaced under the recall, so I had initially convinced myself that couldn't be the issue. I kept having hard starts when hot, loss of power (I could only make 1psi of boost max), and awful fuel economy. I noticed a lot of excess heat under the hood, etc. I did the temp test, and had "normal" readings like you did. I didn't do the "remove the spring bolt" test because the primary AFR sensor is downstream of that, so a drivability test wouldn't prove useful. Long story short, my issue was actually the secondary cat just behind the large primary. The primary was coming apart and clogging the secondary up. I found this out once I ordered the URD Power Pipe and took the 10min to swap over. My old cat sounded like one of those rain sticks lmao. First drive with the catless midpipe and it was blatantly obvious the cat was my issue. I've been running the Power Pipe for about a year now with no CEL's (I have a Vibrant J-bung O2 spacer for the downstream O2) and passed inspection (Since we don't do visual inspections here in commie NY).

TL;DR- Even if you had the cat replaced at the dealer- it's most likely the cat.