Looking for some help with this. I have an IX and my original battery finally died a couple weeks ago. Instead of having it brought to a shop I just ran to autozone and bought a new battery and replaced it myself. The car started up fine and I let it run a little while to make sure everything seemed ok. Well since then the car seems to be driving weird. For instance when I go to pass someone on the highway the RPMs jump really high like I'm shifting poorly and then comes back down and gradually increases again. With this obviously the power seems off when that happens. Is there something I need to get reset now? I never had a battery die on me before on any car I owned. Any help would be great! Thanks!

 

Sounds like a slipping clutch, does it do it in higher gears?

 

It seems to do it through out. The weird thing is it didn't do it before the battery died. It's not just when I shift into another gear either. Say I 'm in 4th and I accelerate a little aggressively it happens. If I could figure out how to post videos on here I would haha

 

I had the same problem, sans battery issue. Turns out I had a boost leak coming from my throttle body. I thought it was the clutch at first as well, cause it would start to rev like the clutch was slipping. Boost leak test the car, then move on from there. Good luck.

 

The higher the gear the easier it is for the clutch to slip. While it is weird that it just started happening after the battery replacement there is nothing in the electrical system that would cause this. If the RPMs are increasing and your speed isn't your clutch is slipping.

 

It seems to happen more during the lower gears. I have a short video of it where I'm in 3rd at about 3000Rpms then accelerate and they jump real quick then come back down

 

Let's clarify this real quick.

Are you in 5th and going full throttle to pass a car and the RPMs jump or are you downshifting to 4th and the RPMs jump while you are between gears?

 

Not full throttle in 5th.. It's basically anytime I accelerate in a gear... Like if I'm at 3000rpms in 3rd and I accelerate but not really aggressively it'll jump up to say 4500-5000 then come back down to 3500 or so then increase normally. I've had the car since '06 so I know it's not normal. I just don't have the funds right now to take it to a place and have them spend hours on Otto not find anything

 

Clutch is slipping, has nothing to do with changing the battery.

 

+1 on clutch slipping. There is no way the RPM can increase without a speed increase while in gear clutch engaged unless the clutch is slipping.

 

+12372168 the clutch is slipping.

 

What if the fluids were low or needed to be changed in the trans? Would that cause something to this affect?

 

No

 

Is it safe to assume that would affect gas mileage too? I seem to be off by 20-25 miles a tank...

 

Yes it would obviously have a negative effect on gas mileage. Get the clutch replaced ASAP. You don't want to be pulling out into traffic when it goes out all the way and have zero response from the car. I have replaced many a clutch on an Evo and believe me and the other 1,000,000 people that have already said this, your clutch is slipping......and yes, it is 100% a total coincidence that you noticed after changing the battery.