# 94 Altima Hard Shifts Weird Electrical



## Bob Harvey (Jan 7, 2012)

Looked around but couldn't find a similar problem so here goes. I have a 94 altima, 2.4 liter, auto trans with 200k miles. Driving the other day the car started shifting really hard from 1st to 2nd and 2nd to 3rd....clunk sound and huge jerk. Also seemed to shift at the wrong time, rpms had to get really high. Check engine light came on plus the car idled rough in park and stepping on the brakes caused the rpm's to fluctuate while in park. Got the car home and took it up to auto zone to check the engine light. On the way there the car ran fine and the check engine light went out. Ran great on the way back home like nothing had ever happened. I pulled the codes from the computer myself and I got 14, 33 and 34 (speed sensor, oxygen sensor, knock sensor). So I drove it around a while longer, went and got some gas, all was great until I turned on the ac. As soon as I did that it started shifting hard again but no check engine light or anything. I am not sure if the defrost was on when it did it the first time or not but as I drove it the second time it definately seemed to shift hard when it was on and shift normal when it was off. Anyone had a similar issue? I don't want to put much money into it but I wouldn't mind patching it up if it'll last 6 more months or so. The more electrical items in use the worse it seems to run (lights, ac, brakes lights, ect..)


----------



## jose a (Jan 28, 2012)

Hi from Mexico, I have the exact same problem with the exact same car, the first time it started to do the that I took it to an automatic transmission shop. and they changed the TPS sensor. The problem stopped for a couple of months, but a little wile ago it started to do the same again. I wold go for some body tat knows about electronic so it wold measure the volts that the TPS sensor is receiving and sending and to see if the use of other electronic in the car is affecting the function of such sensor.


----------



## Bob Harvey (Jan 7, 2012)

Well, I was able to "fix" the problem I think. I bought a Haynes manual and using it I was able to test the O2 sensor and the speed sensor and they both tested normal. I didn't bother with the knock sensor and on the advice from a friend I cleared all the trouble codes from the computer. Once I cleared it's memory the car has been running almost perfect. It shifts normal and seems to have full power. The only weird thing it is still doing is it seems to run with low voltage to the lights, fan blower, ect.., most of the time the lights are somewhat dim and when the heat is on the blower doesn't blow as hard as it should. Other times it all works perfectly....almost like there is a loose connection somewhere. I would think it's the alternator but it's new (reconditioned) and the voltage to the battery tests normal every time I check it. So I'm just living with it. It gets me to work every day!


----------



## smj999smj (Jan 1, 2006)

"New" doesn't necessarily mean "good," and I've seen a lot of problems with aftermarket alternators (and starters and distributors) on Nissans. Check your charging system and make sure it's charging between 13.2 and 15.0 volts. If not, make sure the white, 10 gauge wire to the back of the alternator is in good condition (not corroded or burnt up). If that's okay and the alternator belt is properly adjusted, you likely need an alternator. Whether that has to do with your shifting concern, it's possible, but impossible for me to say. Under or overcharging can cause a lot of different issues, including setting "false" codes in the ECM.


----------

