Hey Everyone,
I have a 2005 Pontiac Bonneville GXP and recently it has been idling well above normal (typically at 7-800 rpm and now its closer to 1500). This doesn't happen all the time, it only seems to happen on the first drive of the day. It's extremely concerning as its trying to pull me into the intersection at stop lights. Shifting into Neutral or Park and the car revs up to nearly 3,000rpm. Is my torque converter gone? Posting a video of it, hopefully youtube links are ok. I appreciate any help I can get.
https://youtube.com/shorts/A6_TW5CskOY?feature=share
Update! Turned out to be a broken front motor mount causing the throttle body cable to fall off the track. Replaced the mount and so far so good.
my torque converter gone?
No. The torque converter is doing what it's supposed to when you move the shifter from Park to Drive. The transmission shifting from park to drive puts a load on the engine, causing the RPMs to slow down.
You're putting extreme stress on the torque converter and it was not designed to take that stress when you shift from park to drive at high RPM. Every time the RPMs spike, especially if you were in park and are now selecting drive, the vehicle lurches forward and most likely slams into gear, which is not good at all, especially with a 21-year-old transmission. Every time you shift from park to drive, and the engine is running at 3k RPMs, you're essentially doing mint neutral drops, which are extremely bad for the transmission.
Is your check engine light on? If so, that may give you some clues to look for. Get a scanner and post any codes you might have on here.
I would clean out the throttle body and check for vacuum leaks.
Thanks guys. I did park that car after the video while I wait to get it in the garage. That hard shift from park baxk into drive was only done once outside of the video. I do have several codes going on relating to higher and lower rpms at idle (P0506 and P0507), torque converter clutch circuit performance stuck off (P0741). am hearing a vacuum leak as well. Knowing its not the torque converter is good to hear as I assumed that would have been more than the car is worth. I'll post an update once I hear what the solution ended up being.
Update! Turned out to be a broken front motor mount causing the throttle body cable to fall off the track. Replaced the mount and so far so good.
Thanks for letting us know! That is reminiscent of GM's first big recall 55 years ago when faulty engine mounts caused unintentional acceleration and other problems. (The "fix" GM came up with was a restraining cable to limit engine movement when the faulty engine mounts broke!)
https://www.autosafety.org/chevrolet-motor-mounts/
Update! Turned out to be a broken front motor mount causing the throttle body cable to fall off the track. Replaced the mount and so far so good.
That's great! Good work!