I have a 2003 xlt 6 cyl and the cel has been on for quite awhile now, when it rains the truck stutters above 55 and uses gas like it is just dropping out. I had it scanned at advance auto months ago and they told me it was the o2 sensor but could not tell me which side and whether it was forward or rear and i was told that the new obdII scanners could tell you which one was bad, and i cant afford to swap all out if only 1 is bad. Like i said before this only happens when it rains and usually stops when it dries out but this time since Monday night it has been doing this and i really cant afford $50 in gas every 2 days. Any help would be appreciated, Any.