Torque Converter Lockup

Hi all,

I have searched these forums, but have not come up with info on my specific problem. My Taurus is having a driveability issue that I think is transmission related. After the car has been driven for several miles and the transmission fluid warmed up to the point that the PCM directs the Torque converter to lockup, it starts having a torque converter lock up problem. When it tries to lock up it seems as though that it can't decide to lock or unlcok. It feels like the car is surging and/or hesitating and after about 3-4 seconds of this, it decides to lock. Its not very harsh, just kind of surges... It does this every time and never changes. I've changed the fluid and filter and it looked normal and it did not change how it drove after it was changed. I'm starting to think that it's torque converter clutch solenoid related... Has anyone else here had this problem? Also, there are no check engine lights. It's a '99 DOHC, AX4N tranny. Car has about 182,000 miles on it and has had the trans fluid changed every 30,000 and has been pampered. It has also had a supplemental trans cooler installed since it had about 100,000 miles on it. Car shifts fine besides the TC lockup issue. Thanks in advance for any help!