well driving a couple of days ago my intercooler pipping blew off the intake manifold..I have evo 9 just with intake....The CEL came on ofcouse so i disconnected the battery and it went off but then it came on just b4 driving it maybe like 3 days later...What could have caused it to come on again?

 

Won't know until you actually scan the code. I had the same thing happen to me and my cat never functioned properly ever again for whatever reason and kept throwing the P0420 until I replaced it with a test pipe. No CEL's to date.

 

so u saying my cat is throwing the code i mean shouldnt it be my intercooler piping that blew off

 

Find out what the code is first. That can save you a lot of hassle troubleshooting something that isn't even a problem. If the car is running ok, then no hurry; just get it read when you have a chance but keep in mind it may go away agin by itself if the problem is gone.
Many auto stores like AutoZone and Advanced Auto will read the code(s) for free. Once you have the code, the community here can provide all kinds of help determining the cause.

 

can i use a snap on tool that reads the ecu my father has one i will have him hook it up to the machine might be a problem cuz its too new

 

If it's a regular OBD II scan tool, it hould be able to read the code no problem. Should be a PO[some number] code.

 

If you got the code while the car was running without that clamp, then yes, I'd venture to say its your cat, but honestly we won't know until you read the code. Just going from experience, I had the same thing happen to me and everytime I scanned my code, it turned out to be the P0420 which was catalyst below threshold, so I'm not sure when I blew that clamp off if it somehow affected my cats efficiency overtime.

 

well hopefully its that but i will be replacing my whole exhaust this weekend with the ams ordered it just waiting for delievery lol also got the ebay cel fix so hopefuly no more problems

 

after taking off the battery again and reseting the ecu, my check engine light came on again....im going to be switching out my exhaust tomorow and taking off the cat. and replacing with a test pipe...Does any1 know why this keeps on coming up ?

 

You should really scan the code to see the problem and see if you are having the same problems as I had. Go to autozone or discount auto parts and tell them to pull the code for you.