Saab hesitation

SwedishWrench,

        I have a 1989 saab 900. The car seems to idle fine. When I press on the accelerator the car hesitates badly. It won't do it if I apply very little acceleration. It does it the worst in 3rd 4th and 5th gears. It has been doing it for some time. It started really bad when I drove it on the highway in the rain and from that point on it's been bad. I disconnected the o2 sensor and drove it disconnected. It acted the same way. So I ordered one thinking the o2 sensor was bad. It has not arrived yet so I can't check that yet. If that's not it I have no idea where to begin. Can you give me run-down on all the things I may need to check. Thanks.

Hi,
        When diagnosing an engine drivability problem the first thing to do is check the ignition system. The hesitation you describe is typical of an ignition system fault. If the spark plugs are worn and the gap is too large (over .032 inch ) you can get the symptoms you describe you must also check the plug wires cap and rotor. When you check the spark plugs you should inspect the porcelain for cracks. If it has been a long time since it's last service you may want to just replace these parts.   
Good luck,

Jason

(This article is meant to educate a consumer,or as a guideline for professionals. You can cause serious damage to your vehicle and/or cause yourself injury. Only those qualified should attempt repairs. I do my best to assure that the above info is correct but take no responsibility for any damages incurred.)

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