I'm near Louisville, KY. For the last 3 mornings, when I started up my 1991 350SD the engine was rough and the car smoked a lot! Since it has been cold, I allow the glow plug light to go out and then usually count to 10 before starting. The glow plug light goes out after it starts but then about 45 seconds later the light comes on again and stays on about 30 or 45 seconds and then goes out. Today I ran 3 or 4 errands and noticed this happened every time I restarted the car. Is this classic sign of a glow plug or two going out? What other things should I check for? On this model the glow plugs are covered by the exhaust manifold. I'm a rookie and wondering if I can handle this job.
JT 1991 350SD