Dear Tom and Ray:

I drive a 1995 Buick Regal two-door custom coupe. In the past week or so, I have noticed that while I am accelerating around 55 to 65 mph, my "Old Man" starts sputtering, sort of like a cough. He has an especially difficult time keeping up speed while going up an incline. The feeling is like a "chug-chug-chug!" along with a jolty-type lurch. My dad thinks it may be the spark plugs. Any thoughts? He has only 82,000 miles, and had only 17,000 in 2002 when I bought him. I'd like to drive him until I am forced to leave him on the side of the road. (I'm very attached to this car.) Thanks! -- Amanda

RAY: I think your dad may be right. It sounds like a classic engine misfire. The spark plugs are the first place I'd look.

TOM: When you're asking the engine to do the greatest amount of work -- like climbing a hill at high speed -- you'd be most likely to notice a bad spark plug. That's when you're asking the spark plug to ignite the greatest amount of gasoline.

RAY: And if a spark plug is weak, the extra gasoline and turbulence in that cylinder actually can douse the spark and cause you to run on five cylinders instead of six. That's what makes the car feel like it's chugging. It is!

TOM: If it's been many miles since you've changed the spark plugs (like 82,000?), start there -- assuming they're not fused to the cylinder heads at this point.

RAY: If it's not a bad plug, it could be a bad spark-plug wire or even a bad coil. You might even consider getting -- wait for it -- a tuneup! Because there may be other things (filters, belts, etc.) that are overdue for attention.

TOM: But give your dad a pat on the back, Amanda. He's steering you in the right direction.