Hello,

My 3.9L V6 is loosing power intermittently.

I tested the vacuum and fuel pressure. 20psi and 45psi respectively. Both stable at idle. I pressed the purge button on the fuel pressure tester and the pressure quickly restored to 45psi. So vacuum and fuel pressure look good, no?

I also just noticed the CEL -- although I don't know when it came on.

Below is the OBDII code, and the OBDII live readings from my budget code reader.

The throttle is also behaving weirdly -- seems to have an unsmooth map between how hard I press and how much power I get. TPS do you think?

Does anyone have any ideas?

Thanks!

Paul


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bump.

 

Bump, and update --

I changed the O2 sensor with a new Denso. I also changed the TPS.

 

didn't realize i'd be overwhelmed with so many responses

well i changed the throttle position sense, the oxygen sensor, and the trans lever position sensor -- which was leaking transmission fluid

it's been a few weeks now and the problem has not recurred.

 

I am not on her often and just saw this. From the looks of your short term and long term fuel trim I would suspect the O2 as the culprit. I have also seen leaks on the exhaust side cause the O2 to act up and give bad readings.