I drive a 98 4runner sr5 with a 5 spd, 189,000 mi. I was driving from WV to NC the other day and started getting a bad vibration when I would get on the gas above 50 mph. When I let off the gas the vibration stops, and when I accellerate the vibration stops, but when I hold a constant speed there is a really bad vibration from my truck. Anyone have any idea what it could be? I was thinking something with the injectors...but dont really have any idea. Let me know if anyone has any ideas.

 

If it fells like a miss...I would suspect either a coil pack or even a wire going bad..any codes? or check enging light blink at all when this happens?

 

No check engine light has gone off. not sure about codes. I havn't replaced the plugs or wires since i've had the truck.

 

i would be looking at your driveshaft first. it sounds like you have a bad u joint. put the truck in neutral, e brake on, and get under there and try to focefully shake the driveshaft. it may take a nice screwdriver in between the u joint to show you that it is worn. if thats not it i would be looking at your tires, rims, etc....anything that spins at high speeds.

 

Check to see if you have thrown a tire weight. The last time I had a vibration at that speed it was due to a badly balanced tire. It would vibrate badly whenever my speed was between 50 and 60 and would disappear above or below that speed range. Once I had my tires re-balanced the vibe disappeared.