OK this light came on the first time i used the a/c in my disco. The next time I used the ac it flashed for a while. i went to Auto Zone and had the guy reset it after he gave me a 1313 code. It stayed off for days and as soon as I used the a/c again it came on? Any ideas?

 

P1313 Misfire Catalyst Damage Fault Bank A , Has nothing to do with the use of the a/c.
What year and how many miles are on the truck, what has been done as far as tune related work?
Mike

 

It is a 96 and has 80,000 miles. The first time it came on was when the a/c was turned on and one of my cats was out. I was waiting for the new y pipe to come in. The cat went out due to a bad injector which was replaced. I had the y pipe replaced and it is running great. After this was done I noticed that it started flashing once when I turned the a/c on. I went to Auto Zone Thinking it was related to the bad cat and if they turned it off for me it would be ok since I had the y pipe replaced. Auto zone turned it off for me and then the next time I turned my a/c on it came on again?

 

I would start with checking the spark plugs, all of them one at a time, looking for a difference if color or moisture. I am think you are gointg to find one cylinder on the drivers side that is having a problem and the cat can't handle it.
Mike

 

Disco mike you gotta believe me! I know this seems strange and dosent make much sense but I really think my a/c is causing my CEL to come on. I did two tests to check my theory. I turned the light off with a tester and drove it both on the highway and in the city for a whole day and it did not come on. then I turned on the a/c and within minutes the light came on. I turned the a/c off for a while and then turned it on again and the light flashed for a while. Then I reset the light once more and repeated the same test and again nothing happened until I turned on the a/c. And the code is always p1313. I just dont get it.

 

What kind of spark plugs and wires are you running? Check them and see if they are covered in soot / carbon.

 

You might want to call me and let's get to the bottom of this.
Mike
303-862-7680
Colorado