My 1998 Pontiac Grand Am GT, 123,000 miles seems to gently buck a little when going up a grade at highway speed.
Does the Check Engine Light start glowing at that point?
Or–God forbid–does it start flashing/blinking?
What is the condition of the spark plugs / wires. A weak coil can cause this, engine on a flat road OK but breaks down under load. IIRC each coil drives 2 plugs.
Which engine is in this Grand Am? It matters greatly. If it is the 2.4 “Quad-4” there are some very specific and well known culprits under the hood that can cause the symptoms you describe. The V6 is an entirely different animal.
What do you have?
Thankyou for the feedback. My 98 Grand Am GT has the 3.1 6 cylinder engine.
What about the fuel filter? Those are often kind of out of sight, out of mind.
However, a weak coil, plug wires, or spark plugs could also cause this kind of problem. So when was the last time the fuel filter, plugs, etc were changed; if ever?
If the fuel filter has never been changed then don’t be surprised at some point if the fuel pump decides to die. That is sometimes a side effect of driving for a long time with a partially clogged filter.
Grand Am GT 1998 has 123,000 miles, fuel filter changed at 60,000 miles and new plugs and wires put in at
95,000 miles. I am going to look into replacing coils and see if that helps eliminate the bucking feel while on the highway.