So on Wednesday night driving home my CEL came on. Pulled the code last night and yup, PO401. so I cleared it, driving the 80 again today and it hasn't come back on yet.
I have 2 theories: one is I am pretty sure I've got an exhaust leak, maybe multiple. Occasionally when I start the truck I can hear something rattle.. I can also get it to rattle at various RPM's, like power breaking while wheeling I can get it to rattle pretty good... second theory is the second guessing of the Landtank MAF mod... which has been in place for about 10,000 miles now.
I can't remember what all got replaced when I had 401 last time, I think the IAC valve? Maybe
remembers... anyway I'm not going to do anything until the light comes on again, but am open to any peanut gallery comments in the interim.