2001 Dakota, 65,000 miles, 3.9L, stick, 2wd
Vibration from 1700 - 2500 RPM, stops as soon as let up on the gas, by “fine” I mean it’s low amplitude and high frequency, the speed of a drum roll. Doesn’t seem to impact mileage or power.
Has it ever had a tuneup? Could be as simple as an imbalance in the efficiency of the plugs or even an injector that’s a bit clogged. not spraying as finely as the others at that speed.
If you are getting a noise, find out what’s rattling and secure it. The jack handle in an E-150 van was my rattler until I put a bungee cord on it.
I had a similar problem with my 2000 Blazer right after the intake manifold gasket was replaced. A buzzing noise was coming from the engine compartment during acceleration. I was able to trace the noise to the gas pedal. When the gasket was replaced a few of the thottle cable tie downs were broken and not replaced. A couple of tie wraps on the cable and the buzzing stopped.
Ed B.
One trick to try is to have the tyres rotated front to back. If that changes things you have a tyre or maybe rim problem.Had that little porblem on a car I had a long time aqo. Turned out to be that the drive shaft dropped a weight and caused the vibration. Had to get another drive shaft from a junk yard.
Take a look at it, can’t loose anything with that.
Thanks all for the good suggestions. I did inspect the drive shaft, couldn’t find any weld spots where a weight may have been lost, I did see a balance weight on the shaft. I can’t detect anything audible that appears along with the vibration, and it definitely comes and goes with engine RPM, it comes and goes in all gears. I’ve never tried to access the plugs, don’t know if they’re hard to reach or what, but will look up a repair manual and start there. Thanks!