black stuff on rear bumper..

[KavG]

so my problem was the poor idle and the bad ground. i got it fixed now i can drive the car but i keep getting black stuff ... from the burned gas im guessing on my rear bumper.. the car sounds diff these days.. and i think ive lost a bit of power... could this be a clogged cat?

any suggestions would help

[RB25-240sx]

the black stuff is actually unburnt gas. your running rich, check out your O2 sensor. I don't think it would be anything to do with the cat. Also, a little more info about your car would help.

[KavG]

92 240sx BEAST! hahahaha

engine wise its pretty much stock except for an intake and mufflerand a chip which i turn on when i want but i rarely do...sometimes the car stalls, and it sounds different.. thats about it...how would i know its the o2 sensor?thanks

[RB25-240sx]

well, O2 sensors go bad slowly, they don't just go out. So it's never a bad thing to just replace it for good measure. as far as KNOWING if it's bad or not, my 95 gave me a check engine light, but i don't know if the OBDI system on a 92 will pick that up. it also wouldn't hurt to clean your MAF sensor. I recently did both of these things to my 95 and it was about $40 for the O2 sensor and cleaner, so it wouldn't really hurt to try these and see if they work for you. I hope this helps.

[KavG]

thanks man

also for some reason a month ago the check engine light turned on and then turned off... so i dunno what that is supposed to mean?

[RB25-240sx]

If it's off now, i wouldn't really worry about it, next time it comes on though, you can put the ECU into self diagnostic mode and it will tell you what it is for.

[IanS]

92 240sx BEAST! hahahaha

engine wise its pretty much stock except for an intake and mufflerand a chip which i turn on when i want but i rarely do...sometimes the car stalls, and it sounds different.. thats about it...how would i know its the o2 sensor?thanks

This chip you speak of, what does it consist of.

Just because the check engine light is off doesnt mean the codes are gone, you have an intermittent failure, the code will have been saved in the ECU, I would pull them to help fix your issues.

[RB25-240sx]

good call, i was thinking he should just wait till it comes on again to check it, but you're right about it being saved, my bad