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Registered
Join Date: Dec 2005
Posts: 1
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87 intermittent severe missfire?
87 Carrera. Issue: Runs fine but occasionally displays a severe miss, seems like the ignition fully cuts off, then restarts almost instantly - engine doesn't die, but if you are driving it is so severe the car 'bucks' and then keeps going. Has had new cyl head temp sensor, and I just replaced the flywheel sensors and O2 sensor (was hoping it was the flywheel sensors, no luck). I did have to remove the bracket for the flywheel sensors so I think they are the right distance off the flywheel but not 100% sure of that - not sure how sensitive those sensors are to the correct spacing. It will display this issue when idling, idle speed drops significantly then comes right back up to idle and will idle fine for a few minutes, then dip and then fine for awhile. What is that?
Thanks, Dirk |
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12-17-2005, 02:53 PM
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UFLYICU
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Try the DME Relay under the driver's seat. They tend to fail intermittently.
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_______________________ Racer Rix Spec911 #5 prc-racing.com |
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12-17-2005, 02:59 PM
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Registered
Join Date: Mar 2002
Posts: 3,563
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Check for vacuum leaks around the intake area, or lower down where the manifold mates to the engine.
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition 
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12-17-2005, 04:07 PM
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Join Date: Dec 2004
Location: Novato, CA
Posts: 3,064
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I would agree with Zoanas. An intermittent cutout would tend to point to something electrical and not something like a vacuum leak, which would have a continuous effect. DME relay would be the first thing to inspect\replace. Also, spend some time seriously going over all the electrical connections in the injection system, cleaning or replacing as necessary. Grounds are very important and there are a couple spots (like on #1 intake manifold) where there are a large group of ground wires together. Any corrosion here will have unpredictable results. HTH,
ianc
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BMW 135i. Nice. Fast. But no 911... "I will tell you there is a big difference between driving money and driving blood, sweat and tears." - PorscheGuy79 |
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12-17-2005, 10:25 PM
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Track Whore
New Daily Driver
Former Daily Driver
