Three months ago, I had the transmission module changed due to the van wasn’t shifting to pick up power. Then last night, it is happening again. I was driving at 40 miles per hour when I noticed the RPM Idle suddenly fell down, then picked up as the car was about to turn off. Just minutes later, when I stopped at the traffic light, the van didn’t pick up speed until I changed from D to L drive ,and then shifted again to D. When picking up speed, I push on the gas pedal hard to get power, but the RPM idle doesn’t go beyond 2. The van pick up speed is so slow until I shift to L gear then D. What can be the problem, the sensor module on the trans. or something else?

Your post is really hard to understand. You might get some feedback if you can rephrase your question to be a lot more clear.

What make/model/yr is van?

Sounds like a clogged catalytic converter or fuel pump, but it needs to be more clear.

It is Nissan Quest 2005 SL. I bought it from New Jersy on ebay and I’m afraid I have bought a flooded car even though the seller said it was never been flooded. My mechanic check it out on the computer and the code came out that the Brain on the trans needs to be changed and we did that and then the van was runing fine till last time start acting the same old problem is the van doesn’t drive properly like the trans stock to lower gear and doesn’t change so in order to make it pick up speed I have to lower the gear to L then after picking up speed I change to Over Drive again but the speed doesn’t go that far. Some friend suggesting to change the whole wiring on it between the trans and the engine with the a new brain box. My mechanic adviced me to take it to a dealer but you know dealers charge arm and legs and if it doesn’t work they try another thing over and over till they drain you out of your money.

It has been over a week since the last time the van acted up and since then I have been driving it without any problem so far. Any clue?

Praise the lord! It healed itself. eBay cars are great!!,

I have a friend that had a car that wouldn’t shift down from high gear when needed. It would shift if he did it manually but not automatically. It turned out to be one of the speed sensors, a $35 part. He changed this and everything was good. If your computer on the trans is going, this is better than the internals themselves.