I know this looks like another cold start hesitation thread, but I feel like I've combed through everything and can't find the same issue.
I'm in Seattle and we're experiencing temps in the teens right now. When I start the Jeep for the first time in these temps, it starts fine and then RPMs dip hard after 1-2 seconds, then come back up and everything is fine. There is a brief CEL during the dip, then it goes away and stores no codes. It has never stalled with this, it never does this even if I turn off and restart directly after, and even later in the day when the engine has fully cooled it starts just fine. Only happens when it sits for more than just a few hours in the cold.
I cleaned the heck out of my IAC maybe 2 years ago by pouring nearly a whole can of throttle body cleaner into the TB while running, just like using Seafoam. It doesn't have any idle issues other than what I mentioned. Oil level is great and looks healthy. Pretty sure I put 10w30 in there, but I may have used 10w40. Coolant is clean and full. Its been a few years but I replaced spark plugs with Autolite XP985s.
My thought is a vacuum issue, but I don't have anything to back that up except for experience with vacuum issues on my carbureted motorcycle. I also don't know why it'd be so brief. Maybe some minor fuel delivery issue in freezing weather? Or maybe this is just what happens when temps are down in the teens and 20s?
Any thoughts on where to look?
I'm in Seattle and we're experiencing temps in the teens right now. When I start the Jeep for the first time in these temps, it starts fine and then RPMs dip hard after 1-2 seconds, then come back up and everything is fine. There is a brief CEL during the dip, then it goes away and stores no codes. It has never stalled with this, it never does this even if I turn off and restart directly after, and even later in the day when the engine has fully cooled it starts just fine. Only happens when it sits for more than just a few hours in the cold.
I cleaned the heck out of my IAC maybe 2 years ago by pouring nearly a whole can of throttle body cleaner into the TB while running, just like using Seafoam. It doesn't have any idle issues other than what I mentioned. Oil level is great and looks healthy. Pretty sure I put 10w30 in there, but I may have used 10w40. Coolant is clean and full. Its been a few years but I replaced spark plugs with Autolite XP985s.
My thought is a vacuum issue, but I don't have anything to back that up except for experience with vacuum issues on my carbureted motorcycle. I also don't know why it'd be so brief. Maybe some minor fuel delivery issue in freezing weather? Or maybe this is just what happens when temps are down in the teens and 20s?
Any thoughts on where to look?
