My6speedZ

iTrader: (18)

Doesn't mean anything, it could be a 9.50 car... just saying

usnfenix

iTrader: (11)

ok and that car is what now? a mustang? an evo? unless its an auto ls1 that doesnt mean ****. driving one car does not mean one can drive all others. thats like saying well i can drive a tiptronic prius so i must be able to drive a supercharged viper.

exactly.

bamalt1

iTrader: (7)

It doesn't sound like your cats are clogged. Does the car smell like straight *** when you drive it? Does it get terrible gas mileage? If you answer "no" your cats should be fine. I would unplug the MAF and see how it drives. It may not even be the o2's and it's free and quick to try.

RPM WS6

iTrader: (3)

Does this car have traction control? On the TCS/ASR cars you can adjust the cable via an inline coupler.

TCS or not, you can use a scanner to check TPS voltage (should be somewhere between about 4.2-4.4v at WOT with a stock, untouched TB). If the TPS sensor is working correctly, this should tell you if you're getting WOT from the pedal. Additionally, if you have someone to help you, you can verify this with a second set of eyes on the TB blade.

Yes, you'll want to check fuel pressure under load, since you're only having problems under load. You might see plenty of pressure when the car is sitting there idling, but that's not when you're experiencing the power loss.

Also, has it been mentioned anywhere in this thread if the car is an auto or manual? Depending on trans type, there are other things that could be wrong causing power to be lost between the flywheel/flexplate and the rear tires.

criticalx

my brothers 96 ta cat was clogged so bad. it would not rav any higher than 2000 rpm when we got his car with 96k on engine. we cut cat off rav up like it should.. maybe it his cat clogged

ZTwentyAteU

iTrader: (12)

fwiw I check EVERYTHING on a ctsv yesterday. Its my buddies car, stock with 100 shot. After checking injectors, fuel pump, springs, pushrods, compression/leakdown test, plugs, wires, etc...I gutted the cats and it immediately fixed it. The car was running lean and clogged up the cats.

RPM WS6

iTrader: (3)

Stock with a 100 shot is not the same as actual stock, and running lean is not usually what causes cat damage. Excessive fuel is the more likely cause of overheated (and thus melted/restricted) cats. I suppose with a power adder like N2O it's possibile that very high temp, lean exhaust gas could also overheat them though. Was the only issue with your friend's car the fact that it was running slower times than it should be? Significant exhaust restriction will usually come with other abnormal driveability issues as well - and this doesn't seem to be the case for the OP.

PS. I forgot to mention earlier, I would also suspect some lower than normal vacuum readings at idle if there was an exhaust restriction (clogged cat), and a further drop in vacuum as the throttle was cracked opened a bit.

I think there are still some tests to perform on this car before changing any parts.


Based on what we know so far, I agree.

youngbird

car does seem to get bad gas mileage
auto
I'm taking everything into concideration but its a A4 LS1. its not very hard to drive. lol. the car can't spin the mickeys on the street why would it do it at the track. A tiptronic prius is prob harder to to drive. BTW can one of you wise LS1 VETERANS show me how to stall the car and step on the gas properly? THANKS.


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Storm Trooper

iTrader: (11)

If I were you I would take the y pipe off now, you have to do it when you have to put headers in soon anyways, drive it around and see if it pulls harder. You can find out sooner if its just exhaust (cats/ o2 sensor) or if it is something else potentially more serious...

usnfenix

iTrader: (11)

Lol kid if you looked in my sig you'd see my first car was a 2001 camaro ss. Owned it for 5 years. I'm picking up a 02 trans am in a few months as well to get back into lsx. I've been on this site for two years now. I'm sorry does that qualify me to speak here about ls1the knowledge? Thought so.

RPM WS6

iTrader: (3)

I've seen you post many replies, but not very much info that we can use to help you.

I've seen no figures posted in the way of:

- O2 values at cruise and WOT
- LTFT data
- TPS voltage at WOT/cable checked for excessive slack
- Fuel pressure (at idle and under load)
- Vacuum readings (at idle and with the throttle slightly open)
- Knock retard/WOT timing data
- Misfire data

Since you are a professional tech, attaining this data should be pretty basic and routine.

Without further info, we are shooting in the dark and it's pointless IMO. All we know so far is that your car is down on power at WOT....a lot, but that the car seems to run/drive fine otherwise. You've also now mentioned that your MPG is reduced, but you haven't specified by how much. Based on this, there are several things that could be wrong....so if you're not going to scan/test for additional data, then just start picking parts and change them.

That is all.

My6speedZ

iTrader: (18)

}BlueFire{

iTrader: (8)

I dont know why everyone is talking about your front o2's when your throwing codes for the rear which do nothing. As has been suggested a full tune up is where i'd start if i were you. Make sure you replace the fuel filter along with everything else, also new front o2's wouldnt hurt but thats not what your code is for. Second A bad rear o2 sensor can throw a catalyst efficiency code so that does not mean automatically your cats are clogged. As has been said however, if it is indeed a clogged cat you would have alot of other driveability issues. Personally start with a FULL tune up. The first thing anyone should do when buying a car is that. Plugs, wires, all fluids, fuel filter, air filter, tranny filter, and front o2's. Obviously not all of these need done but thats what i do. The most important and often overlooked filter is the fuel filter. It can cause lean conditions, poor gas mileage and performance loss etc. Run it again n see how it goes before you change the equation with exhuast... A good strong base will always be faster than a band aid throw parts on and go car

Also you said car does seem to get bad gas mileage... what do you have to compare this to? Since its new to you, i believe you havent had a chance to see the mileage deteriorate not to mention comparing your foot to how others drive is nowhere near accurate. However a good way to test would be straight highway at say 60 mph with cruise is a more accurate test to compare to another stock car... imo

usnfenix

iTrader: (11)

spoken form one of our "ls1 veterans"
goodbye kid, we are trying to help and you arnt following our advice. its your car swap parts and track it then come back here with another thread.

ScottyBG

It's clearly a power issue. Possibly some exhaust obstruction like a partially plugged cat? Time to do all of the basic tune up stuff, new plugs, wires, fuel filter, air filter etc, check the throttle body to make sure it is oppening like it should be. I have seen an improperly adjusted throttle cable where the throttle only opens about half way. Clean the MAF, and the throttle body. Check for vaccum leaks, you may have unmeetered air entering through a rotted out PCV hose or such that would throw off your AFR. Since you bought the headers and Y, I'd go ahead and put them on, replacing the front O2 sensors while at it. This may let you know if your cats are plugged up. I'd do poly motor mounts while you at it, it is a little extra work, but you'll be doing them later if your don't do them now. If your thinking about buying HP tuners, now would be a good time, your could scan the car while driving around and check for KR, you may have a bad knock sensor. Maybe not a bad time to install a wide band as well while swapping in the new Y, if your going to be tuning the car yourself. The only way to know for sure whats going on is data collection.

When I bought my '98 last year I spent over $2K on it just doing regular maintaince items in the first month, just getting the car up to where it should be. That was doing all the labor myself, the $2k was spent on parts themselves. I found things like 2 of the 4 brake calipers were dragging, partially siezed etc. I had a couple broken vaccum lines, need several new sensors, like O2, new MAP sensor, a new OPSU, and both knock sensors. I had issues like the bearings in the belt tensioner, and idler pullies were worn out and needed replaced. When I pulled the shocks off, they were the OEM ones still, and had no resistance left to them at all. Just a ton of things to do on a 14 year old car with over 100k on the odometer. It was a dog, I never ran it at the track. I figured there was not any sense in modding or running an unhealthy car myself. Fix the car first, and make it a good car, spend the money on maintaince items, not performance parts first, that was my approach. After everything was sorted out, and I felt the car was running great for a stock car I took it to the track to baseline it, and got a 13.30 at 103.5. I bet when I bought the car, it would have ran similar times to yours.

WhiteKnight '01

15.5? Are you sure you don't have a V6 Firebird? LOL

Kyle11784

iTrader: (14)

youngbird

just to let everyone know it was a maf

birner88

This post cracked me up. Like talking to a wall.

S8ER95Z

iTrader: (3)

Cleaned or replaced the Maf?