I have been reading through these forums all day and I just can't seem the find what I'm looking for. So I have put on my FLAME suit and decided to post this:

I think my cat might be bad. I am having some power issues with my 2.0 SS and I was wondering if someone can give me a run down of the what happens to the car when the cat goes bad.

My car is not heavily modded, but I am running a few of the GMPP performance stuff, IE: Stage I, II kits w/ the GM tune, and a GMPP Exhaust and a K&N Cold Air intake. Those are the major mods for the motor right now.
My power seems to fall off when I’m running the car aggressive. When I hit about 40 mph in second gear the power goes away. As it hits about 50-60 mph the power slams back on the car launches forward(sometimes the car feels like it hick ups just before the power comes on)(The car does not hick up all the time I have had happen 3 times). When I hit third it runs nice until about 85-90 then the power falls away again. Once I hit about 95-100 mph the power slowly comes back on and the car gets moving real nice down the road. At about 115-120 mph I hit that 4th gear and she running like a BAT out hell. Every Sun morning I run her up to about 130-140 mph on the way home from work.

I just got my new NGK sparks plugs this weekend, so I'm gonna gap them and replace the stockers.
I really started to notice this problem at the last SoCal meet. I notice that cars with the same mods as mine where moving out a lot smoother than mine.

Any ideas are greatly appreciated.

Thanks
Brian

 

interesting..... I got nothing right now...Ill check some things out and ill let you know what i find out. You should ask doc is it could be tuning...maybe running lean...or rich...

Wait...how is your clutch....could it be slipping?

 

what up hotrod..all the norcal guys have found away back on the site

 

I usually think of plugs or knock causing the loss of power. The tune is the same, minus torque reduction and the limited boost in first. Having the dipstick pop out is a key to the cat going, that or something with the pistons....seen that quite often recently.

 

What's crackin buddy it's good to see you guys back. Some of you need to come down to our Socal meet on 07/01/07 and respresent the NorCal guys.

Doc what would you recomend for the gap on the NGK Iridium IX? I really want to replace the stock manifold with the GMPP Header and a downpipe, but right now I just can't do that finacially.

 

sounds about right. I got the same problems AGAIN and since im on my 4th cat id figure your right. The finally symptoms are gas miage is droping hard under WOT pulls and the hiss sounds outta your car in first and begining of second gear. almost like a low wistle. Cats done though. Hicuppa hit around 5500 rpms. also feels like the car is stuck between 100-20 than starts to accelerate again. gut the bitch and be done with the nonsense

 

That is exactly how she feels and the Hicuppa is right around that rpm.