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mooney265 mooney265 is offline
Tinkering Pays!!
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Join Date: Sep 2008
Location: New Orleans
Posts: 1,365
As has been stated earlier: my car always had a bit of a stumble after pushing in the clutch with high [>2500] rpm's.

However, this past weekend, with he onset of very high pressure and cold temps, I adjusted my idle mixture a bit more rich. The car ran much better, however, I noticed that once the weather warmed back up, the stumbling effect increased.

I guess I can "lean it back up." But, wanted to get more at the root of the problem - since it's staring me in the face.

Some history: Like Jim mentioned, I had my throttle body butterfly's hole welded up some years back because I couldn't get my rpm's below 1k with the idle screw all the way in. Once I welded it up, I was able to see 900 when fully warm.

Obviously, this is still too high and points to some other area of concern:
1. Air leak before the TB? I've searched Hi and Lo - - not too sure where it could be?
2. Timing off at idle - - I did have the vacuum pot changed out some years back and am not too sure it's doing what it's supposed to at idle?
3. Idle too rich? I can say my car is much happier now at 12.5-idle than at 13.5. Of course, happier means higher idle, too! I've got the screw all the way in and it's 950 when warmed up...
4. I'm asking this to be sure: could an air leak after the TB cause this problem? My guess is that kind of a leak would only affect 1 cylinder and not all 6...

So, I guess I'm to believe that when others have removed their decel valve, they didn't have to fight the stumbling on decel with clutch in?

I'll try to post a video of the stumbling by tomorrow... Thanks!
LIVN80S - - Red '79 Porsche 930 Steel Slant Nose Conversion [in 1987] w. 46k miles 3.3L; 964 Cams; K27HF @ 1.0 BAR, with Garrettson Intercooler; Rarly Zork; CIS Flowtech Fuel Head & BL-WUR.
Old 11-05-2014, 08:17 AM
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