Serious Problem... NEED HELP
 

So i just drove my car tonight for the first time in a few days (4 days or so) and my car is giving me problems.

1. It won't accelerate properly, it gets to about 4000 rpm before it will shift into the next gear from a dead stop. And I can't floor board the petal and it downshift to accelerate.
2. The speedometer sits at 0 mph till I'm at around 15/20 mph then it will just shoot up and work normally till I slow till about 15 mph then just fall back to 0 mph.

I talked to a friend of mine who works on BMW's for a living, and he said since I haven't ever changed my spark plugs that they could be the issue (i'm at 57000+ miles, I'm just now starting to do my own maintenance before it was up to the dealership). I also called Onstar and had them do a remote diagnostic and they said they was a problem with the fuel management system, but that I could continue to drive my car.

SOMEONE PLEASE HELP ME I'M FREAKING OUT HERE!!!!!

Are you throwing any codes? Automatic Im assuming? What year H3?

I drive an 06 H3.. An yeah I have an engine light on but I don't have a code reader.. I'm gonna run by a place to get it read today.

I also just checked my oil an it's running low.. So maybe that will help of I add some?

I drive an Automatic 06 H3.. An yeah I have an engine light on but I don't have a code reader.. I'm gonna run by a place to get it read today.

I also just checked my oil an it's running low.. So maybe that will help of I add some?

I doubt it would have anything to do with the oil being low, even though I would tell you that isnt a good thing anyways... sounds like you may have a bad PCM... or connections between the throttle body and pcm... something electrical is going on that's messing things up

Forgive me for being dumb but what is a PCM?

PCM= Powertrain Control Module, in short it's the brain/computer that controls all the workings engine wise... There's also a BCM, body controls module that controls the inner workings of the vehicle... Unfortunately I would advise you to have both looked at for your perticular issues and a small shop won't be able to do so...

Well damn I was hoping to avoid the dealership cuz they suck.. But okay!

But thanks for all your help, I can't thank you enough for it! Maybe now I can have a functional car again soon!

It definitely sounds like pcm or a computer to me because all the mechanical systems are functional from what I am reading but they are acting up and are inconsistent. Which usually is associated with computer and software glitches.

Wtf
 

So I took it to AutoZone today and they ran the codes... apparently I have an O2 Sensor problem, and Speedo Sensor is messed up in the wiring. Does that sound right to y'all?