Hi all,
I have some interesting issues in my 2005 Monte Carlo LT. Recently, my engine light has been coming on due to a P0141 code. I already know it's the O2 sensor and the issues most have with it. Peculiar thing though. Recently, My transmission has been shifting weird. 1-2 is long, drawn out, and acceleration is VERY sluggish. 2-3 is very quick with a clunk (feels like the tranny is going to fall out). Downshifting is slow as well when this occurs. Interestingly though, if I plug in my Actron computer and scan codes, I get the usual VSS sensor (driver rear) and have been dealing with that for a while...however, sometimes, the O2 sensor does not trigger any code...but..when I hit Erase codes, the VSS code remains, and the transmission issue stops (for a while). Eventually, the tranny issue repeats..but not all the time. Interestingly, when this happens, I usually pull over, turn the car off..sit for 30 seconds...turn the car back on...then it drives fine. Any ideas? I have already checked the ground from the ABS module and ECM. I actually went so far as to re-drill a NEW ground for them. Could it JUST be the sensors driving the ECM bananas and causing the tranny to get confused? Is it really that simple? My experience with electrical systems in cars (esp American ones) tells me different. Has anyone else had this issue? Any help is greatly appreciated, and thanks in advance!
-Pete

 

Also...when the tranny problem happens and I rev the engine (even in park), I hear a whirring/whining noise. When I turn the car off..let it sit 30 seconds, restart it..the noise is completely gone. SO STRANGE! -P

 

Also, fluid level is perfect (and has been)...car has 89,000 miles on it..and since I have owned the car (since 19,000 miles), the trans fluid has never been changed...

 

I think your having a few different problems .. One sound like the pressure switch in tranny .. The o2 sensor might be bad or catylic convertor might be getting clogged up.. I would be guessing on whirl noise but could be a number of things .. Alternator, power steering fluid low anything with bearings ..

 

Pressure switch in tranny sounds expensive...am I looking at a new one? I am going to change the O2 sensor this weekend. Before that, I may take it to a Midas or Meinakee to see if they can do a backpressure test on it. As for the whirring noise, it definitely sounds mechanical...like coming from tranny area. Power steering/brake/antifreeze fluids are all good. This does not sound good. -P

 

Any other ideas? I am REALLY hesitant to start throwing money into this car. I am at my wits end after reading some of the horror stories on here. I mean I love the car, but at times, I think I might actually like it better if I pulled a "Walter White" and just set it on fire in a parking lot somewhere. -P