99 Dodge Ram lockup convertor issue

Greetings all! The truck mentioned is a 99 Ram 1500, 2wd, 318 engine, and here is the problem:
When cruizing down the highway and the cruise control is set (between
50-70 mph), the engine will "surge". By "surge", I mean the tach will suddenly rev 200 rpm and come back down. I am thinking the Lock-up torque converter is kicking in and out. It rarely "surges" when the cruise control is OFF, although it will do it on very cold days. PROBLEM TWO: After the truck has sat overnight and gotten completely cold, I can leave my driveway and be in overdrive about 1/4 mile away from my house, even when it is 10 degrees outside. I don't think this is normal as every other Chrysler trans I have had didn't hit top gear until the motor had warmed up some. Is this an issue with the transmission fluid temp sensor, or something else. I have taken the truck to a trans shop and they found nothing; no fault codes or anything recorded in the PCM. Has anyone else had this issue? I ask because a friend of mine has a 2000 dakota 3.9 and it does the exact same thing. I haven't had a mechanic hook a scan tool up yet to monitor the trans fluid temp sensor readings as I thought if it didn't work it would throw a code. Any thoughts???
Thanks for your help!! Nick
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Had the same thing with mine. It was the TPS. 15 minute fix to change out the sensor. Somehow the TPS wares out in the spot where your throttle sits most of ther time.
Dave

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Dave, Thanks for the tip. Bought a TPS from work, and installed it. Fixed this very annoying issue!! I always wondered what is was like to have a truck with working cruise control....:)
Thanks again for the advice! Nick
dave wrote:

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Glad I could help. It's about time I was able to contribute here.

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