Night Fury Posted June 26, 2009 Report Posted June 26, 2009 Cruising along, cruise control set at 70. Come over a hill and begin the decent, as soon as the rpm drops because the car doesn't need gas, the rpms drop to about 1000. I cancel the cruise control because there is a speed zone at the bottom of the hill. BUT even with no cruise on, or my foot on the gas, the rpm went from 1000 to about 1700 to 1000 to 1700 to 1000 to 1700 to 1000.... ????????? Quote
RobertISaar Posted June 26, 2009 Report Posted June 26, 2009 IAC issue or vacuum leak or DFCO or TCC? i know CC shouldn't work with a vacuum leak, but when youre in that much of an underrun, theres a LOT of vaccum going through the manifold, probably a good 23" or more... Quote
Night Fury Posted June 26, 2009 Author Report Posted June 26, 2009 DFCO? What is that? And it has never happened before... Maybe something with ac? Quote
Addicted to eaton Posted June 26, 2009 Report Posted June 26, 2009 my tcc will unlock at highway speeds about once every 3 months i notice it. Restart and good to go. Quote
RobertISaar Posted June 26, 2009 Report Posted June 26, 2009 DFCO? What is that? And it has never happened before... Maybe something with ac? deceleration fuel cut off, meaning when you let off the gas at high speed, the PCM quits feeding the motor fuel, essentially shutting it off, but it keeps rotating because the TCC is locked. i don't know if OBD2 vehicles use it, but most OBD1 vehicles do. AC is also a possibility, if the compressor keeps kicking on and off, but i don't think it would go over a 700RPM range. 150-200, i would suspect it, but 700 is a bit much. Quote
Night Fury Posted June 26, 2009 Author Report Posted June 26, 2009 my tcc will unlock at highway speeds about once every 3 months i notice it. Restart and good to go. Not over and over and over..... Quote
89SupremeCutty Posted June 26, 2009 Report Posted June 26, 2009 tcc locking and unlocking? any codes thrown? Quote
Night Fury Posted June 26, 2009 Author Report Posted June 26, 2009 No codes, and there is absolutely no 'feel' to it, as if it was locking and unlocking Quote
sloick Posted June 26, 2009 Report Posted June 26, 2009 my regal has done this for 5 years. i can only notice it when the cut out is open. after i noticed it with that, i can watch tach and it will do it. there is no rhyme or reason to it, it does not do it all the time, just every so often. i just never worried about it. Quote
rich_e777 Posted June 26, 2009 Report Posted June 26, 2009 I seem to have the same problem around 45 to 50 MPH when the gears shift. The RPMs drop considerably and i have to let up off the gas pedal and press on it again to get her going faster sometimes. Quote
Night Fury Posted June 27, 2009 Author Report Posted June 27, 2009 I seem to have the same problem around 45 to 50 MPH when the gears shift. The RPMs drop considerably and i have to let up off the gas pedal and press on it again to get her going faster sometimes. That's the TCC lockup engaging, different than my issue. Quote
Night Fury Posted June 27, 2009 Author Report Posted June 27, 2009 Oh, and Chris? Shaun? Is the 4T65 naturally clumsy and sloppy? Quote
1990lumina Posted June 27, 2009 Report Posted June 27, 2009 Oh, and Chris? Shaun? Is the 4T65 naturally clumsy and sloppy? Yes. Quote
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