Ok, so my 97 318 Ram has had the cat removed. obviously the post cat oxygen sensor will be getting a different reading from this. I have heard of a kit you can buy the goes inline with the post cat sensor to fool it into thinking the cat is there.

Will This effect performance or efficiency of the truck?

Is this little device worth it and is anyone running one?

I'm goin to try and get a price on one to throw in here if no-one does before hand.

Thank you.

 

fastmann (and others) sell a rear o2 simulator that tells the computer that the cat is working. its about $75. it has no effect on performance or mpg, and simply prevents the CEL from coming on.

http://www.thefastman.com/02Simms.asp

 

Great, thanks for the answer.

Guess I don't have to worry about it since my CEL isn't on.

 

Don't worry till it is, and when it comes on, just use a couple spark plug non-fowlers. Cheaper than the O2 sim and works the same. As long as the rear O2 reads differently than the front then you're good.

 

You may want to do a dash light test to make sure that you aren't throwing a CEL. I was surprised that I didn't throw a CEL when my cat got cut out and then I did a dash light test and found out that the bulb is burnt out! I wen't to AutoZone to have them check for codes and sure enough I was throwing a rear O2 sensor code!