Well I guess I can say I've seen it all with my maxima. I've had lots of cars but not one as weird as this car. Over the past few months I've had complaints about my car running top notch one day and then draggin azz the next, even while on the same tank of gas. I've tried injector cleaners, new plugs, different gas stations. I always run 93 octane. The transmission shifted erraticly and acted like it wasn't sure what gear to go in at times. When you nailed it there was a big lag time before the transmission shifted down and the car accelerated. So what gives? Well my battery is over four years old. Very good life I'd say for a battery. My car always starts fine, but last week a couple of times it sounded a little weaker starting than usual. So I went to a shop in town and had them put a load test on my battery. It tested weak and had only about 200 CCA. I'm not sure what its supposed to have. So I put the biggest Optima red top gel battery I could get in there. 800 CCA I believe. Now the starter cranks unbelieveably fast, and the kicker is the car runs like a champ ( consistantly ) nailing it now it spins all the way through first and is still spinning going into second. The tranmission responds a lot quicker, no more lag. The transmission keeps up with the speed changes of the car better. It sounds crazy, but I can't believe the battery had anything to do with it. I know todays cars have a lot of electronics on board, but I figured the alternator would supply those needs, apparently not. Has anyone else experienced this? If your car runs the same maybe check the battery?

 

Could also be because the ECU was reset while there was no battery in the car during the new battery swap. Everytime i reset the ECU it runs so much better..

just my 2 cents ^__^