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Join Date: Mar 2006
Location: Northern Illinois
Posts: 9
Intermittent stumble

I've owned this 87 930 for over 12 years now and it's never let me down... oil changes was basically all that it needed. Earlier this year while taking her out for a typical exercise run and it just quit, coil (Bosch) gave up the ghost, replaced it with a PDL 101-400 transistor ignition coil (Bosch 0221-122-001) and all was good.

Months later, the car has developed an intermittent stumble- losses power but doesn't kill as best as I can tell, (push the clutch in and it stills idling) but will backfire once.

Work done to mediate problem-
New plugs, cap rotor, 2 red fuel relays (all of which replaced the original ones still on the car)

Stumble will not occur every trip but sometimes happen within a 8-10 mile jaunt, after it has the hiccup it runs perfectly...

Any ideas guys?

Old 10-11-2017, 07:47 AM
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CD may be going bad. Sounds electrical to me, but you have replaced the coil. Could also be the green wire from the distributor.

Rahl
Old 10-11-2017, 10:11 AM
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^^^ could also be heat related as you said it happens in a few miles? might indicate cracked or poor electrical connections. see the sticky etc
Old 10-11-2017, 01:50 PM
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Yep, definitely has the hallmarks of electrical issues

Noticed that the cap wiggles easily when strapped to the distributor (more than the normal 1/16th play) so I took a closer look at it last nite.

The tab where the cap locks into the distributor seems to have a bit of a radius on it's shoulders which maybe letting the cap rotate a bit more than usual? The other possibility is that the clamping pressure of the hold down clamps might be weak letting the cap move around...

All that makes sense, but the intermittent part
Old 10-12-2017, 08:10 AM
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You can just bend those tabs down to tighten them.

Intermittent part can be changes in temp and a good backfire can move things around.

Rahl

Old 10-12-2017, 08:54 AM
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