Won't go over 20 mph

It's girlfriends car I will know more in a week when I see her. She said it doesn't rev. Not sure about transmission. No lights are on dash showing issue. She filled it with premium and it seemed good for like 3 days. She said if she takes her foot off gas then back on it will go. Thoughts?

Adding premium and noticing a change may be indicative of fuel system issues: clogged filter, dirty injectors, etc., but letting off the gas pedal and reapplying could point to the fuel system or transmission. The way you can tell the difference is by watching what the engine does. If the engine revs up but there is little acceleration, the transmission is likely slipping, but if the engine speed is not increasing, likely fuel delivery issue.

Update,. I have narrowed down issue. The problem only occurs when headlights are turned on,. This causes all three brake lights to illuminate. Car won't down shift or rev when gas pedal floored. There is condensation in one taillight could this cause this? They are led brake and taillights.

Yes, the condensation may be the cause. COULD be (not to be rude) If the tail lamps are shorting to the brake lights, the transmission may think the brakes are on, and this would cause the engine and transmission to prevent acceleration. You can disconnect that taillight and see if you get a change. Let me know.

It was the taillight condensation. Crazy with no visible crack or damage it's fixed but hope Nissan covers so!email cost as it appears to be a defect.

Excellent. Good find on the condensation! Hopefully they will take care of it. I'm not aware of their warranty program. If not, order an OEM part and replace at home. Too easy to pay an hour (or more) of labor.

Bingo . I been chasing this issue now for a solid two weeks . After reading your post I went and looked at my tail light . Crazy it had condensation in the lens . Nissan wanted a boat load of money for a replacement lens and bulbs . I went old school and drilled two 1/2 holes in the bottom of the lens . Water drained . Problem went away . Thank you very much !

This is happening to my 2014 Nissan Sentra. My cars like new very low miles under 20,000.... It seems to not allow acceleration when headlights are on and since I got the car it's frequently had condensation in rear drivers side light?? Crazy..I turn the lights off and it goes?? Did drilling the holes fix completely?? Thanks for helping!! Ughhh!!