My D4 light is blinking after driving it a few minutes. I notice that when it hit 55mph before the RPM was going down to 2200 but now stay in about 2500-2600. Also notice that i'm having a bad gas milage. I change solenoid and VSS. does anyone know what might be the problem?

 

get the code from the Trans computer and tell us what it is. Once we know the code, we can tell you what the problem is. My guess based upon what you have said is a torque converter lockup malfunction. If the solenoid is bad, you will have to replace it and that isn't gonna be cheap since it is usually inside the transmission.

 

i changed the solenoid already, i will go to get the codes. suggestions for any places.