Seasoned Veteran Poster
Join Date: Jul 2002
Location: Overland Park, KS
Stumbles upon initial Acceleration?
Been dealing with this issue for a while and am running out of ideas.
1997 Thunderbird 4.6L
AED SuperCharger 103k miles
When I first attempt to accelerate with the engine cold, it stumbles all over itself. It will do this for about the first 2 minutes, then the issue goes away completely. This is just normal acceleration as I pull away from the driveway and make the turn onto the first couple of streets to get out of the neighborhood on the way to work.
By the time I get to the first stop light, it accelerates perfectly fine, no issues. Operating temperature isn't fully warmed up, maybe up to 100 degrees at this point. I can watch on my scan tool to see if I can pinpoint that if it matters. Doesn't have even the slightest hint of this issue until I go to leave from work after the car has sat all day. Exact same thing, first few accelerations stumble really bad, then it clears up.
I don't believe it is a misfire issue; no backfire and no codes, and idles perfectly even when first started. Any thoughts on what to check. Mechanical issue or an issue with the tune perhaps? I have two different tunes from two different people, and it acts exactly the same with either one, so I am leaning towards a mechanical issues of some sort. I have searched out and tracked down any possible vacuum leaks.
During the past 4 months I've replaced the following:
Plugs & Wires
Intake Manifold Gaskets
Its very consistent. Does this every time on cold start, regardless of outdoor temperature.
1989 Cougar XR7 - 13.21 @ 102.29 -SOLD-
1993 Thunderbird SC -Awaiting Suspension-
1994 Mark VIII - 14.85 @ 93.95 -SOLD-
1996 Thunderbird Sport 15.57 @ 89.42 -Retired @ 258k-
1997 Thunderbird LX AED -SOLD-
1997 Thunderbird Sport 15.71 @ 86.89 -SOLD-
1997 Mark VIII LSC 12.97 @ 112.15 -SOLD-