rough idle, 95 grand am gt

[jeter1955]

Hello, i have a 1995 grand am gt with 146,000 miles on it. the engine is the 3.1 v6. It idles real rough while in drive, and you can hear it miss through the exhaust. does anyone know what could be causing this problem. The check engine light isnt on either, so if that eliminates anything. Also, while im driving trying to hold a speed 50 and higher the car shakes real badly. thanks for any help

[poof]

try for the next 4 or 5 fill-ups putting some fuel injector cleaner in it.

[Slade901]

You might want to check the condition of the spark plug wires.
A lot of times the spark plug wires are laying on the engine block, exhaust manifold and they will rub. Over time the insulation is exposed and you will either get a cross fire or intermittent grounding of the spark plug wires.
Try using some spark plug wire separator and some tie wraps to separate the spark plug wires from each other and away from the engine block surface and exhaust manifold.

[Chubes]

HAve you checked if there are any codes stored? You say the check engine light isn't on, but it can come on for a short time only and then go off, setting a code in the ECM. Have you ever had the O2 sensor replaced? If not, then it's time.

[ryanheath]

ya I had the same problem when my car was changing gears it would shake badly. I replaced the spark plug wires and it runs a lot better. but i still have a rough idle from time to time