Thanks to Dan Hansen for contributing to this FAQ!
I had a problem with the check engine light coming on after buying a 95. The light would come on, then it wouldn't come on, then it would come on & so forth. Got the same codes p1312 & p1334. Put in some high octane gas & viola - light has not come on since! The p1312 refers to cylinders 1&2, the p1334 refers to cylinders 3&4.
Thanks to Robert Lester for contributing to this FAQ!
I have run in to this issue on my Aero after I bought it, and also on a 900 I had before the Aero. In both cases the Mass air flow sensor was at fault. I told the mechanic to check this when i first started experiencing the problem, and on neither car did they check. I sourced re-manned parts and both times it solved the issue. Parts are easy to replace as well. When the codes reflect the mixture being too rich or too lean and be sure to check the mass air flow sensor.