Taubr Unit

iTrader: (32)

My buddy has a '00 camaro with a lq4 swap, cam, ls6 intake etc..basic combo and 6sp. Bought the car about 6 months ago and it ran perfectly fine and strong! Car sat for 2 weeks while we put a rearend in it and now it has nothing but problems. First start and drive it runs perfect and strong, one it gets up to operating temp (closed loop) it runs like ****. It will idle fine but anything over half throttle it just falls on its face. Let the car sit and cool off and runs fine again until it gets hot and runs like **** again.

Car never showed signs of issues before it was parked for 2 weeks so why all of a sudden it runs like **** when hot? We put new o2 sensors in it and it got even worse when hot so now I'm really lost. Any tips or anything else we can try?

93camaro_zzz

iTrader: (13)

Sounds like some issue with O2 sensors. Maybe there is an exhaust leak upstream. But it reasons to me that if the car runs good in open loop, and then only starts to run bad because of closed loop, which is taken exclusively from O2 sensors, that the O2 sensors are the problem. This assumes that your closed loop settings in the tune are accurate, which I would assume they were.

Taubr Unit

iTrader: (32)

That's why I keep leaning towards bad o2s as well being different ones made a difference just not the change we needed. And I don't think it's the actual tune being it ran like a animal and perfectly fine before it sat for 2 weeks. Is there Any way to test o2 sensors?

93camaro_zzz

iTrader: (13)

Only way I could think of to test them would be to be logging the narrowband voltage, and have a wideband on the car, hopefully very near to a narrowband, and compare the 2. If you are using hptuners, you can play with VCM controls and the commanded AFR to see at what afr the narrowbands switch at. You know what I mean?

VandykeT/A

Let the car go into closed loop and look at fuel trims. Everytime I've had a failed 02 it would show a false lean or rich condition but flooring the car puts it back in open loop and should clear it out. Normal driving should be where it shows the most. Unless LTFT is stored extremely lean I can't see it being the problem lean LTFT is applied back to wot but that would be adding fuel. I've also seen cars with weak fuel pumps going 17s on my wideband at wot but never misfire. Just no power.

z28a4

iTrader: (1)

Where did you get the o2s from? I've had terrible luck with parts house sensors. I stick to gm sensors now and haven't had a problem since. Just speaking from my experience.