This is a newly rebuilt engine. That I have yet to work right. Car runs great when I am in open loop or when I have the O2 sensors disconnected. As soon as it goes into closed loop I can't accelerate worth crap. Even though I have no codes showing these certain sensors bad I went ahead and replaced numerous ones.

Replaced
1. Both O2 sensors
2. Maf sensor and Pigtail
3. ECT-Engine Coolant Temperature sensor in water pump

Maybe I have an exhaust leak, but wouldn't I show a code for a lean condition in one of the banks???
Maybe I have a vacuum leak. I checked vacuum and it is at 11-12 or so. But I also have a fairly big cam.
Any thoughts? Thanks.

 

Are you able to get a scan tool with live data on it? Check to make sure your O2s are doing what they should on closed loop. Possible you could have exhaust/vac leaks, but won't always check a code. Also, being this is a new engine, is it tuned for all your mods? Any backfiring?

 

Are any of the wires for your O2's burned between the ECU to the connector.

Get a datalog, it should tell you if your sensors are working correctly.

Good Luck

 

Hi, What about a Tune, MAF cal. could be off?

 

The engine has been tuned(mail). Had two different people tune it thinking the first one may have mistuned it. But came up with the same issue on both tunes. I have a aeraforce gauge that scans the pcm while the car is running. It shows both MAF and O2 sensors reading.