Around December of last year I was leaving work and I started my car up just fine and it idled like normal. When I put it in gear to leave I pressed on the gas and there was no acceleration. The car would creep forward when in D and backwards in R like any automatic would do but I had no acceleration or throttle response in either of those gears. When I put it in P or N I could rev it just fine. No check engine or other indicator lights came on and no codes were stored. I turned it off and tried to restart it and it was an extremely slow crank and all the dash lights flashed rapidly like it was putting on its own rave. So I immediately went to low voltage. From doing testing at school I already knew my battery was about done so I replaced it that night and everything was fine until a couple of moths later. Early this year I was driving home when my car just randomly started to slow down on the road. I tried to depress the accelerator and nothing happened. RPM's continued to drop until I pulled into a parking lot and came to a stop. The car idled fine but when you tried to give it gas in D or R nothing happened. The RPM's stayed the same. However if you depressed the accelerator in P or N it would rev up just fine. Again, no check engine light or stored codes. I turned the car off and let it sit for a minute and when I tried to restart it, it was a slow crank like the battery was dead. My alternator had begun to make noise and I knew it was probably shot from driving with a bad battery for so long before I replaced it. So I installed a new alternator and everything was fine until about a month ago when it did the same thing again. I'm kind of at a lose here because the symptoms to me indicate low voltage, and mimic a dead battery or one that's not getting charged, but the battery and alternator are brand new. The problem is also so intermittent that I have a hard time believing the battery or alternator is the cause, although faulty parts can happen. And once you cycle the key, it will have a slow crank like its not getting enough volts but it will start and be fine for another month before doing it again. I have not checked current battery voltage or alternator output yet. I plan on hooking my TPS and APS to a digital scope to see if signal drops and correlation between the two is putting it in limp mode. I don't believe that is the problem because most manufacturers allow the car to go at least 20 mph in limp mode to safely get off of the road. Sorry for the long post but I want to include as much information and detail as possible. Any assistance is much appreciated! I will include my vehicle specs below.

Vehicle: 2004 Nissan Altima 2.5S

Summary: Intermittent loss of acceleration, will not accelerate/rev in D or R, can rev fine in P and N, cycle key and slow crank but runs fine again, new battery, new alternator.

Hello. I have a 2003 Altima that started doing the same thing. A week ago it also included me getting a jump start on a battery that's only 6 months old. Had no starter problems since but 5 more episodes of no response from the accelerator pedal. I took it to the dealer for diagnostic with nothing found to be a problem. The next day after, the same thing happened near the dealer and was able to limp the car there so they can experience it themselves. He experienced what I have been telling him personally but his diagnostic guy was off and told me to bring it back the next business day. I'll see.