Was having a few problems with my I35. Some days she runs good other days she ran like crap recently. Now today she started up fine, no shaking smooth idle. So ive noticed that slow driving is fine, any mid thottle input was very slow. SO im like well maybe the exhaust is clogged up. I was driving the other day and the car seemed like it wanted to shut off but never did. So i took it to 3 places and confirmed that the battery was dead or it had a dead cell. I want to know before i spend the cash on a new battery if this is the main cause of the problem. I do have an ebay knock sensor on my car and it seems to have been retarding the heck out of my timeing anything more that mid throttle is spark knock rattle sound.

 

When my battery was going bad it would start up fine sometimes and need a jump start on other occasions.

Btw I got an oem knock sensor, pm me if you're interested!

 

yeah the car starts up everytime fine and it will drive down the road pretty well until mid throttle it get sluggish like something is not getting enough juice ect. Thats the part I dont get. My 3rd gen had a dead cell once and i didnt know it, all i know is it wasnt running 100percent like it was before, so then i took it to get a replacement battery and she was back to normal, never had starting issues or anything. Batteries now days are expensive so ill see if it needs some water before i go out and get a brand new one.

 

MAF or precats?

 

Yes, a bad battery cell would definitely cause driveability issues. You can't really postpone your battery replacement, so I would just go for it and replace it.

My battery also went out recently. I suspect one of the cells went bad as the battery voltage was down to 11.2-11.3V. The car refused to start, and it did exhibit a number of funnies, like radio playing/not playing, lights on/off, etc.

 

I've seen them not start even with jumper cables from shot batts, but if it starts under the batteries own power...
It would make sense if the alternator was weak and the bad batt was killing voltage that it would act weird...but then we're back to it cranking without a jump, plus the brake and batt light should engage from low voltage.

 

[QUOTE=Child_uv_KoRn;9109015]I've seen them not start even with jumper cables from shot batts, but if it starts under the batteries own power...
It would make sense if the alternator was weak and the bad batt was killing voltage that it would act weird...but then we're back to it cranking without a jump, plus the brake and batt light should engage from low voltage.[/QUte

Yeah it starts up everytime i go to crank it. Thats the part that has me confused if its a dead cell even though it seems as if some parts of the car are not getting the juice like normal. Just 3 weeks ago I was flying down the road at 85mph now i can barely hit 70 without the car bucking/jerking. So maybe this is the issue as it seems like everthing was going wrong lol I did recall going to have a battery and alt check 2 months ago and they said both were good. Now i go to get both checked and 3 places confirmed a bad battery. Well only one way to find out. Another unexpected expense lol.

 

Ive got a few mafs to swap out, but even with one of the pre cats kinda bad the car would still run like a bat outta heck, pulling hills at 75-85mph steadily.