I should probably hold of on starting up a thread on this because I am not ready to dive in to this, but oh well.

I was driving to work in the Regal this morning when I noticed the tachometer riding a bit higher than usual. I start fiddling with the controls, and found the RPMs were moving around with minor adjustments to the throttle, instead of engine speed being directly locked to vehicle speed. An engine restart at speed yielded no change, and the problem was still present on the trip home later in the day.

Forum experience suggests wonky TPS and Brake switch are the biggest culprits.

For some background I was out with a car in a dirt lot getting an idea on how the brakes were reacting in extreme situations. The brakes have been a concern but I'll save that for another thread when I throw more at it.

I plan to plug the scanner in to it and see what is going on with it sometime in the future, mainly because it'* hot during the day and I don't feel like messing with it. My gut suggests the excursion in the dirt lot poking at the brakes may have upset something, but I also wasn't looking for this issue while driving either yesterday, and the car sat for over a week even before that. Cruise control is still working fine, although it seemed unwilling to pick up speed with it. The cruise control controls in this car have always been finicky in this car, but the issue persists even when CC is not engaged.

More to follow when I start poking at it. I feel like this is going to be one of those times I am glad I have the scanner and FSMs.

Today I plugged in the scanner in the driveway. No stored codes, TPS values are steady and consistent. It does show that the "TCC Brake SW" is "ON', however I seem to remember that being the case before the issue arose.

Given that I believe this model can detect if the TCC and associated hardware are not behaving properly, I am assuming at this point that lockup is simply not being commanded, which helps put my mind at ease for the time being on the expensive and complicated fixes. It also reinforces my gut feeling, the brake switch.

Next up is the road test with the scanner to confirm suspicions, which will be left for another day.

At cruising speed of 65mph, and level ground, rpms should be under 2000 RPM'* if the TCC is engaging...

I usually cruise at 70mph, which calculates at 1916RPM, and sounds consistent with what I have seen in the past. The car now cruises at 2000-2400 depending on load, and never settles down like it does when the TCC locks. Also, touching the brakes at speed while on the throttle lightly now yields no change in vehicle behavior at all, where as in the past, the TCC would unlock, and RPMs would rise in to the range I am seeing now. I also see higher 3rd gear engine speeds than typical at cruise as well, despite the gear selector position.

It'* not working, I am 100% sure of that.

If you have checked the obvious stuff (brake switch) take it to a transmission shop and have them read codes. Your scanner won't read the necessary codes.

Which codes won't show up? I was under the impression that tranny codes show up under powertrain codes, and any code reader will pull any powertrain codes (OBD 1.5 aside)

Your impression is incorrect. Even my code reader that will pull ABS codes will not read transmission codes.

We have some very cheep scanners for general use from Auto Zone and they have no problem at all pulling up transmission codes.

Time to up date your scanner

rjrolly87 go take it for a drive and put your foot under the brake petal and pull it up see if its acts normal then.
Brake light switch could be just sticking enough to cause the problem

Admittedly, the Regal hasn't seen much road action lately, but I decided to check in to this a bit further today because I was out for a nice empty stretch of interstate driving, and I happen to have the scanner with me.

Immediately, I was greeted with a code:
P0703 Brake Switch Failure
P0703 ? Torque converter/brake switch B -circuit malfunction ? OBD Trouble Codes

Kind of surprising, but not really. I would have thought it would knock out the cruise control at least, but I guess not. Brake lights and everything else seems to still work. The only symptom is no TCC lockup.

I had ordered a brake switch when I first started having the issue (they are cheap), so I guess I may as well get to putting that in soon. It'* obvious there is two parts to the switch in looking at it, and likely the bit that goes to the PCM has failed.