Throwing codes, inspection overdue. HELP!?!

[FirstOnRaceDay.]

My car has expired plates and inspection. I took it to get inspected and everything passed save it throwing a few codes. It's telling me i have a misfire,upstream 02 sensor slow response code (x2) and that it's running rich. The car drives fine, as far as i can tell from driving feedback i can't tell that there is any misfire. The only mods to the car are long tube headers, offroad H, flowmasters and a built clutch. There are no cats on the car but it does have the MIL deletes and is not throwing any codes for no cat or the converters not working properly. I bought a bottle of Seafoam but has not used it yet as i didn't know if i should put it in the gas tank, vacuum line, oil, or a combination. I have cleared the codes and driven it very nicely and the codes continue to come back. I have tried cycling the codes out multiple times to no avail. I have very little money to spend on my car at the moment so new cats or o2 sensors are out of the question basically. I know others out there have had this problem and i have pretty basic mods.

Can someone please tell me how to take care of this as cheaply as possible. All i need is for it to pass, i know someone out there has the answer so please help me out guys.

 

[FirstOnRaceDay.]

Have been doing some homework and found out how to do a few things.

so far i've come up with:
seafoam car
change plugs
change wires change all filters
change oil
clean imrc's
clean upper intake
clean maf

does anyone know if i could remove and clean my o2 sensors? links to write up on cleaning maf and o2 sensors would really make my day

 

[TDUB003]

Run the Seafoam through a vacuum line, pouring in just enough so that the car doesn't die. Shut the car off wait 15 minutes, fire her up, and prepare for a smoke show.

 

[harvboi05]

Have been doing some homework and found out how to do a few things.

so far i've come up with:
seafoam car
change plugs
change wires change all filters
change oil
clean imrc's
clean upper intake
clean maf

does anyone know if i could remove and clean my o2 sensors? links to write up on cleaning maf and o2 sensors would really make my day

check the resistance on the 02 sensor, that will tell you if theyre bad or not. haynes manual should have the how-to for it. dont bother cleaning them. however, i bet the slow response time for the 02s is bc you have long tube headers. a proper calibration will take into consideration and adjust your primary 02 sensor response time due to their relocation with LTHs.

everything you mentioned is good preventative maintenance but i dont think it will fix any of your CEL issues.

 

[FirstOnRaceDay.]

check the resistance on the 02 sensor, that will tell you if theyre bad or not. haynes manual should have the how-to for it. dont bother cleaning them. however, i bet the slow response time for the 02s is bc you have long tube headers. a proper calibration will take into consideration and adjust your primary 02 sensor response time due to their relocation with LTHs.

everything you mentioned is good preventative maintenance but i dont think it will fix any of your CEL issues.

does a proper calibration mean i need a dyno tune?

 

[harvboi05]

not necessarily, but it would need to be custom. its one of those, might as well get it dyno tuned while ur at it, kinda deals.

 

[PSUCOBRA96]

change the up stream o2 sensors and replace the plugs, if there is still a misfire try replacing the wires.