95 Weird Vibration at 45 mph on hill

I have had my girl (1995 Avalon XL) for almost a year, and I have noticed when I am going about 45 mph uphill, there is sometimes a weird vibration for a breif second. If I let off trottle and try again, it won't do it. Any ideas on what this could be and if it is serious? TIA

I wouldn't sweat it right now but, it sounds drivetrain related, possibly the transmission or inner cv joints on the axles.

Thanks. I have had one cv joint replaced, and I think the other needs to be done soon, but it isn't bad yet. I know the tranny has had a rough life til I had it, it is starting to slip. Nothing worth worrying over right now, just starting to show signs. When I got the car, I took it to "Mr. transmission" and told them about the shaking, and the guy said it may just need tune up with spark plugs. He didn't even look at it, or drive it or anything and pretty much wanted me gone. It usually does it when I am steady but somewhat accelerating between 43-47 mph. When the other cv joint was replaced, it made a knocking noise when I turned right and this one (if thats what the problem is) isn't/ hasn't done this (yet).

Thanks again.

When the time comes here's a little info. Your car has 4 cv joints. Two on each of the two axles. The inner cv joints connect the axle to the transmission. The outers connect the axle to the wheel.

Generally, when you hear a click during turns it's an indication of a bad outer cv joint. When you hear clunking or feel a vibration during acceleration or deceleration it's an indication of a bad inner cv joint. The cv joints are covered by rubber/vinyl boots. They can tear with wear. They need to be inspected periodically. Generally when a CV joint goes bad its because the boot has torn allowing the lubricating grease to leak out and dirt/grit contaminates the joint making it fail.

Thank you so much. You are the man. Your knowledge is GREATLY appreciated.

I realize your post is dated and hope you have found a solution but wanted to add an caution to RIP's post. My boots were torn and decided to replace the axels. The caution is unless the mechanic is VERY careful about how he does the repair, he can very easily damage the ABS sensors. This will cause the warning light to stay on when you start the car. Replacement of the sensor(s), to my knowedge, is the only option. I found out the hard way and it added $150 to the bill.

Well, it actually pretty much stopped doing this. But, sad to say... the car died on the 10th of March. :( The rear main seal was leaking, but wasn't much. Then all of a sudden, it completely gave out. We are thinking it messed up the engine as well, and now I am looking at a new car. Probably looking at Gen 3 V6 Camry.