Mechanics

ROUGH IDLE

1996 SAAB 900 • 179,000 miles

Have new di cassette, no vacuum leaks, new platinum plugs and fuel fitler. Idle varies, sometimes very rough and sometimes not as rough. Code 1170 shows misfire. Could this be caused by a fuel injector or engine computer. Also periodically there is a loud humming noise on drivers side. Has new clutch. I getting tired of trying to fix this car.
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Porteous
September 26, 2011.



It cold be a bad wire, plug or injector as well as low fuel pressure will cause a misfire. A vacuum leak will as well. Fuel pressure should be 43.5 psi

Hmac300
Sep 26, 2011.