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940T sometimes fouls the plugs 900

Have a 940T with about 95K on the engine. Twice in the last month the car has failed to start when it was cold. (Also happened once last spring.) Both times I removed the plugs and found them gas fouled. Dried them out, cleaned them up, and put them back in. Car starts right up and everythings seems fine. Have had a couple occasions when the car would start and run real bad, like it was not firing on all 4 cylinders or running real rich. But, if driven a little, the engine would suddenly clear up and run just fine.

I am not getting any problem codes from the OBD. The air filter is new. Checked the O2 sensor, and am getting voltage varying between .3 to 1.0 volts just like you are supposed to get. To measure the O2 voltage I had to disconnect the sensor. The OBD noticed the O2 dropping out and sent me the proper code. So, I know the computer is seeing the O2 sensor. Ignition parts are all new within the last year. I put in new plugs at one point to see if this would help. But it did not. Thermostat is recently new and seems to be working fine as the engine temp. gauge is steady at roughly vertical when the engine is warmed up.

I am stumped on this one. If it were a carborator engine, I would know what to do. (Screw driver down the carb. throat to hold the choke plate open. Crank until the engine belches a ball of fire. Then the engine starts and runs fine.) Normally the car runs and drives fine. If this were not the case, I may suspect the air mass meter.

Being an inconsistent problem, it is difficult to trouble shoot. Making matters worse, it is my wife's car. It has stranded her twice. This is not a good image for a Volvo owner.

Any thoughts on this problem are greatly appreciated.

--
Gary D






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New 940T sometimes fouls the plugs [900]
posted by  Gary D  on Mon Feb 23 09:03 CST 2004 >


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