I wish I would get a code 12. I'm just running out of options to test. It started last year. A couple of cool temp starts. Not even in the minus. But it would miss alittle and clear up. Never happen again all day. Then slowly got worse through the season, only morning startups. Some farts and sputters then causing a single start stall. This season, 3 start stalls minimum. After 10 secs, runs excellent.
New plugs, the 9's
A tank of seafoam now passed through. Supreme only also
Tb's synce
Brand new battery
Coils tested and dielectric applied
Tps 16-98. Smooth numbers with no glitchy spots
Exup wired fully open...
Adj CO from minus 10 to plus 10. No change
Propane tested for vaccum leaks
All grounding blocks inspected and greased
Scrubbed throttle body plates with cleaner.
Iac valve and airbox sensor swapped for known working ones.
Tested with belt off primary.
It's a real pain to diagnose cause I only get one chance a day when its cooled off. The rest of the day it starts great. Runs strong.
So every day this week I've been trying something new... I even thought it may be a low voltage or voltage sag upon start up. So I attached through booster cable my deep cycle marine battery. It did turn over that morning alot faster than normal, but exact same fart fart studded stall.