You'd check them first and, if found faulty, replace them. (Although they aren't that expensive) Good luck with it.

 

Knock sensors are not expensive anyway...you could buy one at autozone for pretty cheap. But yea, it needs to be replaced. Buy coolant to when you buy the knock sensor, because you will loose all the coolant in the block for bank 2 when you replace that knock sensor.

 

how can i check em?

 

IDK how you could check them. If the code is coming up, its probably bad. That same knock sensor on my mom's Bonneville went bad (bank 2). Replaced it, cleared the code, and everything has been perfect since!

 

what could be causing it to give me the knock code?

 

A bad knock sensor is causing the code. Honestly, thats all it probably is. I am willing to bet, replace your knock sensor, erase the code, and your problem will be solved. (at least the knock sensor code).

I have no clue whats going on with your gear ratio stuff???

 

i just had my transmission rebuilt.
u think my jackass mechaninc messed something up?
if i tune my PCM to upgrade my shifts, would that fix it?

 

How soon are you to get the downpipe on and the tune (PCM)???

I say do that work first, then clear all the codes and see if something pops back up. You never know if the clogged cat is forcing other things to screw up or be screwed up.

THEN if those codes come back, you'll replace the knock sensor.

 

Umm, I think there might be a relation between having your tranny rebuilt just recently, and throwing a code for gear ratios! I would just take it back and make him fixed it. Sounds like he screwed up something with your gear ratios...

 

X2 on replacing the KS, clearing the code and all should be smooth sailing. The gear ratio problems could be a heck of a lot more involved. If you follow the links I posted you'll find that For a Code P0730 to set, the PCM must detect an incorrect gear ratio caused by excessive slip within the transaxle: to be exact, a gear ratio that is off by more than 5% for more than seven seconds. The PCM will only tolerate shift timing as high as .65 seconds, pass that and it maxes out line pressure long before the shift timing has maxed out. You'll need access to a scanner to be able to perform the tests, gear ratios evaluation for all gears for example, and might even have to drop the differential if all the testing shows all sensors and gears to be in good working order. If you have to drop the diff, there a torch test I've read about (I've never done it) that could shed some light on the problem, the reluctor being loose to be exact, and save you from having to buy a new diff unit. Check the links out!