There is definately something with your computer/sensors. I know that
until the engine reaches running temp, there are verious sensors that
are set to open circuit. I do not know the whole list of them other
then the O2 sensor, which would not cause that issue. The engine you
put into the car, was it the same as that that came out? If the
transmission and engine type are not the same as what the ECU was
programmed for, this would be your issue.

"CenturyTek" > wrote in message t>...
> I completed the change a couple days ago. Vehicle starts, runs fine. After
> 15-20 minutes on the road the speedometer becomes erratic, fluctuating
> rapidly up and down, eventually after about a minute, settles to zero, where
> it remains until the vehicle is stopped and allowed to sit for a while. The
> auto shifting becomes irregular after the speedometer with higher than
> normal revs being required when it does finally change.
> A 30 minute cooldown period allows the vehicle to perform correctly for
> about another 15-20 minutes at which time the erratic behavior happens
> again.
> I have seen posts indicating the eeprom might need a reflash.
> Does anyone have any ideas about this problem?
> TIA
> CenturyTek