OK... Been trying to diagnose this all weekend. Bought 6 new spark plugs, NGK Copper type. No help. (Engine builder sent Autolite Platinums.) Swapped fuel injectors with no. 1 cylinder. No help. Using a noid light, I tested the wire for the fuel injector. When I start the engine, the first couple flashes are nice and bright, then they get dimmer. I tried cyl no. 1 and the same thing. I thought maybe an electrical issue. Went and had battery tested. Failed! Replaced battery and it was not the problem either. Thing is, if I clear the code, I can drive it for miles without throwing a code, but then if I stop and shut off the engine after 15 minutes or so, then I throw a code. It seems that the computer runs on default settings for a while and then adjusts, because the idle also lowers at this time. After resetting, it runs 750 or so, and after the 15 minutes, it goes to 600ish. That's where I throw a code. Could it be that the alternator is just not charging properly causing a low amperage situation? It seems like when I throw my battery charger on the battery and also run the engine, it won't throw a code then either. Like when I run for 15 minutes and then restart it it throws a code, but if I put the charger in first for a few minutes, then no code. I really am at a loss here.
I think I will be suggesting that they take it to the dealer tomorrow, or give me my money back and I'll buy something else somewhere else.