I have been having problems with my truck in my sig. I am currently running complete open loop. When I start it, it will run rich (13.5ish AFR) until it is warm. When the engine is warm I can drive it for a very long period of time without problems and my AFR will stay right around 14.6. If I park the truck even for 15 minutes it will run horribly lean (like around 19 AFR). Once it reaches this point I literally have to park it for about 5 hours for the problem to correct its self. I have adjusted everything that I can possibly think of without it working properly. Something that has me stumped is that I am not adding any fuel at all for warm up. I would think that it would get richer as it warms up, not leaner. In case anyone is wondering I have my IAT mounted in the cold side of my wet intercooler just under my radiator, and it is usually right around ambient temp. I have also mounted it in the back of the intake manifold with the same results. It seems as though I get this problem because my aluminum intake is warming up from the heads and transfering to the injectors, and lines. Any help would greatly be appreciated.
Thanks,
Daryl