Tired of searching... Less power everyday

[Desertwind16v]

You have no CEL and it runs fine otherwise, my money is on a clogged cat. Is there any pressure coming out of the tail pipe? You could also drive it for a little bit when it feels real down on power and then get out and look at the cat, see if it's glowing or crazy hot (just don't touch obviously) If it's possible you could also unbolt the cat (funny, I know) and see how it drives without it on.

 

[thegipper]

This is what it was like when the cat clogged up on a crappy Mazda Tribute my wife (then girlfriend) owned at the time.

Probably a long shot, but figured I'd throw it out there.

Not a long shot at all, that's what I'd put my money on.

OP, check your cat to see if it is clogged. You can use a IR gun and measure the temp before and after the cat.

 

[4Runnin2000]

Not a long shot at all, that's what I'd put my money on.

OP, check your cat to see if it is clogged. You can use a IR gun and measure the temp before and after the cat.

I will try to get a hold of an infrared gun. I think I saw a cheap one at harbor freight. Any other ways to diagnose a clogged cat? And what would cause it at 150k miles?

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[thegipper]

I will try to get a hole dog an infrared gun. I think I saw a cheap one at harbor freight. Any other ways to diagnose a clogged cat? And what would cause it at 150k miles?

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They can just go bad over time, 150k miles on one that is failing is not surprising.

There are other methods:

remove the upstream o2 sensor so the exhaust can escape from o2 sensor hole
remove the cat entirely

IR gun is the easiest way, temp should be higher on the down stream side of the cat. Eric the car guy has a good video on how to test the cat with an IR gun on youtube.

My grand prix had pretty much the exact same symptoms as you described and it was my cat.

Good luck

 

[Difflock]

Cats have a life cycle. If your emission laws, and inspections laws are lax just cut it out. Or get a high flow one. You use a temp gun or a live reader to diagnose it


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[Tyler James Inc]

I have to disagree with the recommendation of taking the cat out to see if it runs/drives better.
I drove my 2nd gen 4R to the exhaust shop after I 3.4 swapped it, and the incredibly loud exhaust made it completely impossible to feel how much power it had- or didn't have. It makes so much noise, I couldn't possibly use this method to diagnose a bad cat.
Maybe some guys can; maybe I'm an odd-man-out on this.