what are some problems that would cause knocking? I only hear it when it's idling. could that also cause rough idle?

 

Pre-ignition, overheating, incorrect A/F ratio, bad fuel, wrong timing, lack of fuel (something plugged), excess carbon build-up, low oil level...

 

would a bad fuel pump cause it? or a fuel pressure regulator? i have problems with it taking longer cranking to get it started. if i turn the key on but not crank then back off it starts easier. would it be a related?

 

They could, yes, with me leaning towards the regulator. A bad regulator can and will cause starting issues (multiple cranks to get it started) and also a rough-running engine. You could check your spark plugs too and see what they look like. If the FPR is bad, there's a chance the plugs could be fouled up which would cause poor ignition and subsequently a poorer/rougher-running engine.

 

Ok, i also have got the code po172 too rich. i changed the upstream o2 sensor already. i replaced the wires and plugs a few months back. i'll to check the new ones. i tried changing the iac and map sensor and seen no changes. i bought a new fuel pump. i just to make sure it isn't it. would it be easier to just replace the fuel pump or the regulator?

 

The regulator would be easier to replace than dropping the entire gas tank to change the pump. Too rich would mean too much fuel (and an incorrect A/F ratio), so your plugs are probably going to be wet.

 

i checked one of the plugs. it didn't seem to be wet. just a little black

 

Black will do it too. That's fouling from fuel.