Cat banging against cab at Idle

Hi all,

I've had a problem for close to a year now with my 1997, 2.7L 4x4 DLX. At idle or reverse with a passenger, the exhaust makes a horrible sound. I'm going to describe it as a banging as opposed to a rattle. Metal on metal. I know these 2.7's tend to shake and I've decided not to go down the route of trying to balance out the engine. I was hoping someone had an easy fix, like maybe a loose heat shield or a bolt I need to tighten. I've tried to tighten what I can see with no avail. I'm 90% sure it's coming from the cat, because it only happens when the wife is sitting in the passenger seat (I know what your thinking, but she only weights 115 or so) and that's directly below the passenger seat. I'm hoping someone's dealt with it before. I've found next to nothing online so far.

 

does it still make noise when driving (in motion) and not idling?

 

No, the engine vibrates less when it gets over 1,000 rpm or so. Only at low idles basically, stop lights, reverse, etc... so noise stops while driving

 

well i too have a rattle down under there somewhere but only while driving it seems. it resonates at 2.1k rpm but only mildly unless A/C was on (then its maddening!) like my whole truck is going to fall apart, then it goes away only to return in the next gear
there is no idle rattle that i can detect so its been a pain to find out what it is for the past 7 months or so. I cannot find any loose heat shields or anything!

 

It'll be a heat shield likely rattling. With it parked and idling with park brake on have your wife sit in it while you use a long pry bar or screwdriver to apply pressure to different parts of exhaust until you find where exactly where the rattle is. Then once you see where it's coming from, you can use stainless hose clamps to go around the shield sometimes and tighten them up. Ask here if you find it but aren't sure how to address it.

 

Could also be a motor mount or tranny mount that is starting to break down and allow things to touch that otherwise wouldn't. Just something else to keep in mind when you're doing your poking around underneath while wife is in there. A big long pry bar works good for lots of diagnosing crap like this

 

i am now heading to Utah, weather permitting on i80 (of course)

 

Okay I'll do that. We'll see what I find this weekend.

 

Is that a pic of it? The one in your avatar? Looks two tone and all trimmed out, I like that look

 

i am going to say its bedliner type of stuff along the bottom?
watch me be wrong (again)

 

Yep that's it! Just two tone regular paint. Yeah the Deluxe's are nice, all metal bumper, sun roof, electric windows, love it. Pre TRD, they called it the '4x4 outlaw'. I've got the old style pickup manual hubs which are awesome. Only been stuck once. I've never seen another one like mine.

 

Looks like the two tone color schemes Toyota and Lexus were using in the 90s, kinda why I thought it might've been done by a dealer or it was a repaint and they did the second tone there on bottom. But that second tone matches the step color and that looks like an original step doesn't it? So maybe the second paint tone is original or somebody did some excellent designing and picked that second tone to match the color of step. Or second tone was there when truck was acquired and they got a step and it just happened to be a similar color to the second tone of truck paint. We'll find out soon enough

 

You must've meant to quote minelooks sweet hermano. Post up some pics

 

its a small pic and i know you can get colored LineX bedliner, saw a white Line-X liner yesterday on a white truck
just a guess
i saw a red Tacoma on TW here with black bedliner along the bottom, though it looked good is all

 

one one of my 4 cyl tacomas there was only 1 exhaust suspension piece by the cat with no provision for another and this one pulled the exhaust toward the frame. On the other there were 2, one towards the trans and one toward the frame. I had to weld some round stock to be able to pull the exhaust back towards the trans on the first one. Is yours this way... dont know, it is something to look at though.

 

Check the rubber exhaust hangars, they get all dried out and fall apart over time and when that happens the exhaust is able to swing around all willy nilly under the truck. You can buy new ones at AutoZone for like $4.

 

I had a rattle that ended up being a broken exhaust manifold...but that was more noticeable while driving and not idle.

 

I guess you ruled out anything broke or loose under the seat since it seems to only happen when the right seat is used !!

115 pounds or another few pounds more should not cause the cab to move enough to cause noise.

Cracks in the floor ?? Broken Rusted Cab mount might cause enough movement but should be easy to see

 

Mine did this & then started happening when turning left. Turned out that someone sitting in the driver's seat was just enough to have the cab kiss the frame. The verdict was new cab mount bushings....