Help! Hesitation at idle

[doubt at inwave.com (Nate Mellom)]

John,
I had the same issue with my '88 16v.  I ended up replacing the O2 
sensor, adjusting my timing, and adjusting my mixture.  I don't know 
exactly what did it, but it solved my problem.  I'm still running rich, 
I think, but it's an issue I'll deal with at Cincy.  Do you have a DPR 
test rig?  Makes it easy to adjust your mixture, or you can just eyeball 
it by adjusting and revving.  The adjustment screw is on the fuel 
distributor, just right of the fuel connections (looking at it from the 
front of the car).  It's a 3mm Allen to adjust it, righty richy, lefty 
leany.  It doesn't take much turning to make a difference (start with 
1/4 - 1/2 turn).
Nate


John C. Worden wrote:
> I am trying to get this car ready so I can take it to Cincy, but I can't 
> find the cause of
> this final issue.  The car is an '86, originally an 8V now a 2.0 16V.  
> It idles well now, though
> it does vibrate quite a bit, but that probably is due to the hard rear 
> mount.  When I give it some
> gas it kid of stumbles or hesitates for a moment before reving.  It 
> really only seems to do this
> under 2k.  If I let off the gas at, say 4k or 5k and hit it again before 
> it drops below 2k it revs
> right back up.
> One noticeable thing that may or may not be related- the car is running 
> rich. I
> don't know why,  and not really sure what I can do about that.
> I did think about the gas- what was left in the tank was lower 
> octane(3-4 gallons) and have
> since added 92 octane, seafoam and today techron along with some more 
> gas.  Since doing
> this it idles better, but my suspicion that the old gas, and it was old 
> was unfounded when
> I took 5 gallons I drained from it and dumped it in the truck and it was 
> fine.
> Any thoughts on this?  Tomorrow is my last day off before I leave for 
> Cincy, so I would love to fix
> this problem tomorrow.
> 
> 
> 
> John C. Worden
> Bucksport, Maine
> 
> ''98 Dakota 4x4-
> '86 Scirocco 8V-Now a 16V!
> '78 Scirocco Brazil Brown Metallic, 4 speed.- In the Rotisserie and 
> under restoration
> '89 Polaris Indy Deluxe
> 
> 
>