Torque Converter/Transmission Electronic Problem?

[eddieg4724]

Hello! I have a 1998 Grand AM GT. The car is a great car besides this problem and one other with the cruise control which is also posted. The engine's rpm usually stays at about 1600 rpm with the torque converter engaged. When you let off the gas or ascend down a hill when the cruise control is engaged, the torque converter will disengage raising the rpm to about 2000 rpm which I know is normal. The problem is that this happens extremely often and sometimes can occur within the invervals of 5-10 seconds jumping up and down- disengaging and engaging repeatedly. Sometimes it jerks and is not smooth when it does this. Could this be an electronic control problem? I also have a problem with the cruise control not staying on and having the resume it very often. I'm not sure if these two problems tie into each other. Could anyone help me out here? I really appreciate your time. Thanks!

- Eddie

[robry]

possibly your brake light switch, or the lookup sensor in the tranny. I have a feeling its your brake light switch. Try it sometime, when the tranny is in tq converter lockup. Press the brake slightly when you have your foot in the gas keeping the tq locked. It should unlock. I think its a few dollars for the part, vs tearing into your transmission to replace any type of sensors in there.

[rixGAphx]

Combined with the cruise issue, I truly suspect electronics having to do with the battery/alternator/cables.

The PCM just doesn't control the tranny very accurately if the electrical power isn't strong and 'clean'.

With the engine speed going up-n-down, so is the voltage from the alternator.
Thus the TC solenoid may get enough power to engage, then lose power and disengage.
Engine speeds up, electrical power increases, repeat .....
* * * * *

That's my theory, and it's based on slightly more evidence than 'flat-earth' :D :D.

Anyway, it costs virtually nothing to check and clean and tighten the alt/batt/cables.

-Rick

[04GASE1]

deffinately a brake pedal switch