This car was sitting in the garage for more than year and now it is realy lazy almost not drivible. When I shift to D and start moving it was fine. Plenty of power to get car moving. When driven on interstate at 60-65 mph rpm would stay around 2000 all the time. When I approach the hill car does not downshift to maintain the speed but start stalling. When I stepped on the gas it got even worse, it will almost stop. I have to pull into right lane and slowly recover speed. First I thought that it was transmition filter so I replaced it and the fluid. (I had the similar problem on my 1994 explorer while back and this solved the problem). After refilling the transmition it took for ever for transmition to even engage. I was reving the engine with gear shifted to drive and car was sitting in the place. Gradually it started engaging but still with long delay. Now I got check the engine light ON. Could it be transmition failing to shift or mayby catalytic converters plugged. I will go to local Advanced Autoparts Saturday to have them read error codes to get some idea. Any input is appreciated.