Problems with 97 Grand Am

[Ditterstick]

Hi,
I have a 1997 Grand Am Se 2.4 Twin Cam engine automatic trans.
I have had the car for two years the second day I had it after I bought it the engine spun a rod bearing.I went to the dealer and bought a new GM engine half price$$$. Things when ok after I installed the engine until my first winter with the car.I first noticed that when it got really cold the cruise control wouldn't work unless at or above 45mph. Secondly when I let off the engine the Rpm gauge would bounce between 2-3 grand when mph below 60 or above 45. Althought if I shifted into neutral it would stop. lastly I noticed that the Check engine lite will sometimes come on with a P0507 code.IAC right, well I replaced sensor,cleaned throttle body,checked vacuum lines, and electrical connectors. Still having someold problems I don't know what else to do only does this during cold weather . One more thing I also noticed that when slowing down from highway speed the lights and heater motor dim for a second as if the alternator is kicking out.
Any help would be useful when the Check Engine lite comes on the traction control stops working. That means winter driving is tought

[xeroinfinity]

Welcome to AF.

Your cruise isnt suposed to work under 40mphish.
On the boucy rpms its hard to say, when was your last tune up ?
These dash clusters are kinda flaky anyway.

The p0507 is idle higher then expexted...
You could have a sticking throtle cable, or you didnt calibrate the IAC, or its port is partialy clogged.

On your lights dimming, could be a low battery, bad ground, bad alternator or just being the POS these cars are.
Very typical on Grand am's because the stock 100-105 amp alternators are kinda under powered for all the electronics that run.

ANd if your traction control kicks out then you should get it scanned with a ABS/Trans capable scan tool. Probly a wheel speed sensor, another typical problem...


Hope that helps.

[Ditterstick]

Thanks for the help,
Maybe I forgot to mention that when the rpm gauge bounces I can't hear the engine doing any such change,it feels more like the torque converter kicking in and out.If I brake really hard the bouncing stops,I mean when it does this the whole car shutters.I'm thinking the problem is inside the transmission. Secondly I had just tuned the engine that fall new oil,filter,fuel filter,trans filter/fluid,spark plug Etc the total works. I also took the entire throttle body off the intake and cleaned it. Lastly what I ment about the traction control is that on the new GM cars when the Check engine light comes on it puts this feature in limp mode.Little did I know this but read it from another post.But makes since because it works as soon as the light goes out.Funny thing really the light came on today and after about a hour of drivng it went out.I'ved checked everything but run the wiring for bad spots. I normally have good luck with GM products since it's all I buy I guess if I don't figure it out I will wait this this summer when it stops and sell it.
Thanks