I have a 1997 Mazda 626 with 84,000 miles on it (LX). Everythime I start it (almost everytime) after it has been sitting overnight or for a long time, it shoots out a huge cloud of grey smoke! It goes away fairly quickly after I start driving, but if I just sit there it smokes. Anyone know what the deal is?

 

it is usually caused by a clogged air filter; mazda carburetor, choke, fuel injection or emission system malfunction; ignition timing off; or a blocked manifold. so I suggests that you check on those things. give us an update of what other things did you find out. good luck

 

Valve stem seals which are worn usually allow oil to run down into the cylinders after shutting the car down. It'll smaoke on start-up, but the smoke will go away after a few seconds, and you won't notice much of an oil loss because it doesn't take much oil to cause a considerable puff of smoke. Probably not worth fixing until you replace the camshaft....if you ever get to that point.

 

Blenster, if you have not done that for a long time try to replace fuel filter and clean injectors – I know at least one guy whom it helped to completely beat start-up smoke, but he had white smoke, not grey.