I thought I had an exhaust leak before but after tightening the nuts, changing the gasket and eventually getting a new header I still am having problems.

There's no cel yet but the car is now switching in and out of closed loop. Torque says its due to insufficient temp. My coolant reads as low as 188 on the highway and the manifold is insulated to the cat so the o2 sensor heats up well.

I get a sputter when letting off the gas or shifting and the fuel trim leads towards the positive rather than the normal -5.5%.

Both sensors will read normal and then go to opposite voltages, stay almost dead then it'll go to open loop.

Any idea what it could be if its not an exhaust leak? ECU? Bad upstream sensor- could that cause funny readings from both o2 sensors?

I know Texas Honda had some input on my initial thread but that wad when the problem turned out to be a leak found by using seafoam. Almost the same problem except its worse.

Thanks

 

So is the exhaust leak fixed?

Either way, if the temp is not getting to the proper value then yes it will not go into closed loop. Why, well that is the fun part. T-stat stuck open, ect getting out of spec, ect?

 

Im pretty sure the exhaust leak is fixed. I should triple check again but thats whats annoying me cuz I completely fixed and replaced everything up to the cat converter. Then when I started up the car again it ran fine until I got on the highway.

If the thermostat were stuck open I wouldn't be able to get up to temp so fast though and I dont think my car as an EGT... Or did you mean ECT? Im not sure what that is.

Heres the data from that initial trip

https://docs.google.com/file/d/0B3nQ...it?usp=sharing

 

My car is idling somewhat normal now. I did an exhaust leak test, no leaks. Vacuum reads about 22.8. Thats a little lower than normal.

I did notice some fuel around the filter banjo bolt. I tightened it. Ill replace the washers soon. Could that cause these problems?