Well... forget the alignment "study" for now ... Driving the other day, check engine light popped up, figured initially was perhaps fuel cap issue as I don't always crank it til I get lots of "clicks".... checked / turned it a few clicks. Anyways, since it wasn't going out after a "few restarts" (probably about 10 times), I got out the "torque app", read the code, P013b... slow responding o2 going from lean to rich...hmmm. Anyways, cleared the code. Light stayed off for a few more "drives" but then popped up again... :-( Different this time though, after about 4-5 starts, light goes out. OK. Not!.... about 2-3 times later, light pops on again. Get the torque out and same code.
So now the hard part, figuring out what the heck is it complaining about. So of course, the top of the "list" indicates potentially a bad o2 sensor (unlikely but maybe). Picked up another Acdelco and dropped it in, cleared the code / reset the pcm via fuse removal. Things seemed to be fine... not!... about 5-6 starts later, code pops again. :-( During the o2 change out, the old looked fine (now a spare), cleaned the throttle body, checked the connections (vacuum wise)... maybe the gasket on the "out" side of the throttle body could be changed as it maybe is less than well sealed (it sits in a "receiver groove" in the port to the intake).
Looking thru torque, in the test results "tab", the tests associated with the o2 sensors seems to be passed / checked including the response time one... ???
One set of tests that don't seem to be working / running is an evap test for .040" (whatever this is... the .020" is successful) and the cap test.
I don't notice much / any drive issues at this point... maybe a slight mileage decrease but hard to tell with changing weather conditions and mostly city driving.
Sorry for the "long story", I guess the questions are... where do I look next? and what's up with the different evap tests / cap test ... perhaps they don't apply to trailblazers / chevy.
Thanks for any comments and guidance. Hopefully, I can get this addressed before it does a tune on my cat. One other thing, GM did replace my exhaust manifold under the recall 2 years ago. It still appears to be intacted (fingers crossed) so I don't think its an exhaust leak.
One other thing that perhaps I noticed from looking at some of the freeze frame data, is that the speed was around 50mph the couple of times that I looked at the data.... kind of strange that it was in the same general speed as city driving typically doesn't get you in that area except in certain surface road areas.
So now the hard part, figuring out what the heck is it complaining about. So of course, the top of the "list" indicates potentially a bad o2 sensor (unlikely but maybe). Picked up another Acdelco and dropped it in, cleared the code / reset the pcm via fuse removal. Things seemed to be fine... not!... about 5-6 starts later, code pops again. :-( During the o2 change out, the old looked fine (now a spare), cleaned the throttle body, checked the connections (vacuum wise)... maybe the gasket on the "out" side of the throttle body could be changed as it maybe is less than well sealed (it sits in a "receiver groove" in the port to the intake).
Looking thru torque, in the test results "tab", the tests associated with the o2 sensors seems to be passed / checked including the response time one... ???
One set of tests that don't seem to be working / running is an evap test for .040" (whatever this is... the .020" is successful) and the cap test.
I don't notice much / any drive issues at this point... maybe a slight mileage decrease but hard to tell with changing weather conditions and mostly city driving.
Sorry for the "long story", I guess the questions are... where do I look next? and what's up with the different evap tests / cap test ... perhaps they don't apply to trailblazers / chevy.
Thanks for any comments and guidance. Hopefully, I can get this addressed before it does a tune on my cat. One other thing, GM did replace my exhaust manifold under the recall 2 years ago. It still appears to be intacted (fingers crossed) so I don't think its an exhaust leak.
One other thing that perhaps I noticed from looking at some of the freeze frame data, is that the speed was around 50mph the couple of times that I looked at the data.... kind of strange that it was in the same general speed as city driving typically doesn't get you in that area except in certain surface road areas.