I have a little story. Three years ago my car was having serious lack of power and hesistation problems. I didn't have time find the problem, so I took it to this guy that works out of his garage and is reliable and reasonable. He replaced the cat and the O2 sensor. The cat was disintegrated and completely plugged. This obviously blew up the sensor. After that the car could lay 40ft of rubber with a touch of the pedal. But then it went back downhill.

Some of you have probably seen my posts about this. So now it's got a similar problem, but not near as severe, with a backfire every time I rev it up to 3000+ and shift. My car backfired for a long time because of a MAF sensor problem. I fixed that but shortly after it started backfiring again. Do you think I blew up the cat with the backfiring and I've got the same problem again?

 

I haven't seen your other threads...

But have you checked your timing? Running rich? Tons of things to factor in..

 

ok, v6 laying down 40ft of rubber? im not really bieleving this unless u mean a brake stand. but it makes sense that if your engine isnt running right, and it clogged the original cat, and u replaced the cat without fixing the problem with the engine, it is very possible that the new cat has also clogged or been otherwise damaged and hurting performance.

 

I know there's lots of other factors. I just want to hear opinions on this possibility.

And ya 40ft of rubber, no brake stand. I can't do a brake stand with my 5 speed. But with crappy tires and a dropped clutch, I layed 40ft.

 

you're running rich for some reason, no doubt. Leaky injectors, low compression, bad ignition system, bad timing, all possibilities.

 

i would pay to see a 2.8 lay 40 ft of rubber i think they are the most nutles engine around but thats me.

 

2_point8_boy: Ya, running rich is a definite possibility. But not from timing, and likely not from compression.

z28monster: No one wants your smarta$$ comments here.

 

Oops, I see where i said something confusing. I meant that the cat could be dead again because of raw fuel going into the cat. Some reasons for the raw gas getting past the combustion process could be those reasons. If you have a leaky injector, too much gas is getting into the motor. If you don't have the timing set right, the engine is misfiring and not burning the correct amount of fuel while it's in the engine. Low compression will also do the same thing since gas burns faster(explosion) when is compressed. If you take away the compression, raw gas down the pipe.

I learned the compression lesson first hand. I had a cracked exhaust valve when I got the car, so the #1 cylinder wasn't firing and it ended up melting my cat.

A bad ignition system will cause a misfire for obvious reasons. When my first coil went bad, I didn't know what the symptoms were and I went so long dumping unburned gas into the exhaust that it melted the cat. It clogged up 100%, I had no power what so ever. I couldn't even drive the car down the street to get a new one welded on.
Hope that clarifies a few things.

 

I think I confused YOU. I understood what you meant in the first post, it was clear. I was just saying that the timing is definitely fine. The compression I'm pretty sure is also fine. But it wouldn't hurt to check. It's pretty easy. Thanks for ideas.