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Replace catalytic converters?

Mike1276's Avatar
CF Beginner

Join Date: Mar 2017
Posts: 1

March 19th, 2017, 9:39 PM   #1  
Replace catalytic converters?

Hello all,
First post here. I have a 2008 suburban with 117k miles on it. I've had it almost a year now and overall runs looks very nice. I feel like the vehicle isn't getting necessary power at highway passing speed, like the exhaust is restrictive. Has anyone here found that replacing catalytic converters at 100k has made noticeable difference as far as restrictions? Planning on putting on sway bars, shocks and bigger rotors/calipers up front but exhaust would be my first start if needed.

Scotiapilot's Avatar
CF Senior Member

Join Date: Jan 2015
Posts: 310

March 20th, 2017, 1:43 PM   #2  
I have the same year mine has 373 gears. has 121K miles. never has felt that way. Id suggest making sure injectors are clean, (run techron on a few tanks) inflate tire properly, I run 39lbs. remember heat and warm temps always makes a care feel sluggish. During the summer I run super and it always brings back a lil more power and pep. because the engine uses the higher octane to advance ignition timing and fuel curves.
Generallly give her a tune and filters. I also run Royal purple. oil which is good for another 1-2 hp lol.
Bad convertors will get scorching hot and you will throw codes.

in2pro's Avatar

Join Date: Apr 2008
Posts: 7,353
Austin, Texas

March 22nd, 2017, 10:32 AM   #3  
The likelihood of bad cats is slim, unless you know the vehicle has been running poorly, with things like leaky injectors, bad plugs or wires , heavy oil burning, things like that will cause the cats to clog and become inefficient. If the vehicle has been over all well maintained and isn't burning oil or smelling like un-burnt gas then the cats are probably fine. Dragging brake calipers, worn wheel bearings, dirty air filter, and general tune up is where I would start. Use the OEM plugs they will perform the best

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