Car vibrates during acceleration

Hi, have a honda odyssey 07. I just I just got an alignment done on Tuesday night. I think it drove okay. I sent my car to Costco last night to get 2 new front tires replaced. Took the local road home last night and didn’t notice anything wrong. Now I am driving to LA from SF. As soon as I hit the freeway, I noticed my car vibrates uncontrollably when I accelerate at the speed btwn 65-7mph. However, it seems okay when my feet are off the gas pedal. Any input ? Should I stop driving? I am driving w/ 4 kids . I would like to know if my car is safe.

Stop and check the lug nuts on you tires. Also, go to the front of your vehicle, about 30-50 feet in front, get down and look at the front tires. Are they perfectly vertical?

You have a lug nut wrench in your vehicle, its with the jack. Use it to see if you can tighten any of the lug nuts. Because that wrench is so small, it is unlikely that you can overtorque the lug nuts, so if they move at all, then get to a shop and have them torqued down properly.

Check the rear wheels too as Costco will not mount two new tires on the rear unless you just bought new tires for the rear. The will move the rear tires to the front and put the new tires in back.

I agree with Keith. Re torquing the lug nuts would be the first thing I would do. Torque wrenches aren’t that expensive and it’s worth having one around. I never trust discount stores for tire work and check myself. When each wheel is off the ground, if you know how to check for excessive front end play, do it. Check tire out of round. Some of these don’t appear to be your problem, but check regardless.If all else fails, a trip to an experienced mechanic or the dealer for wheel balancing and checking may be in order. You should be ok with tires within 2/32 inch from front to back. If they are, I would leave the new tires on front and rotate in 5 to 6 k. Get it looked at regardless ASAP. “uncontrollably” does not sound good.

I’m in agreement about this being an out of balance tire issue (old rears moved to the front) or the possibility of loose lugs.

Since you had an alignment performed I would add one thing that I’ve seen a few times. That is someone putting too much toe in or out during the alignment or worse; not tightening the lock nuts on the tie rods. This can allow the tie rods to unscrew themselves from the tie rod ends and can possibly lead to an abrupt loss of steering if it gets down to the last half a dozen threads and decides to strip out.

Do not take a trip anywhere until this is resolved and get it looked at by someone close to you. Drive at slow speed on the way to a shop too.

(Regarding that loose tie rod lock nut scenario, that happened to me some years ago when I used to commute a long way to work. My wife had tires put on the car and the tire store did an alignment at that time. We started to leave later in that car and I noticed after pulling out of the drive that the car was thunking and felt funny. Instantly back to the driveway where I discovered both locks were loose and the left side was almost completely unscrewed.)

I thoroughly disagree that this is out of balance tires. Out of balance tires would be felt in all conditions - not just on acceleration.

I think this is CV joints.

I’m with CapriRacer re: the balance issue - inner CV joint or bad motor/transmission mount would be my first suspects.

Its also possible that there is a misfire going - or some other engine related problem. Heck it could even be a TCC clutch that doesn’t want to unlock when accelerating.

I don’t know why it couldn’t be a tire balance problem, which can come and go with varying speeds.
A short time back I was on the turnpike (I usually avoid them) and noticed my car vibrating a little at the 75 MPH posted speed limit. Backing off to 73 and under would smooth it out. The next day I checked the tire balance which showed to be off a bit and all was well after rebalancing them.

There’s also a few unknowns which may never be known unless the OP posts back. This involves keith’s comment about moving the used rears to the front and the always lingering question; was there any lesser vibration leading up to the complaint speed?

People can sometimes be pretty oblivous to noises, vibrations, ride, and performance problems on their vehicles.
A few years back my daughter bought a new set of tires for her car at Wal Mart. Several weeks later she was visiting and circumstances dictated that I go somewhere with her. The minute we hit 30 MPH I could feel something was wrong (not to her) and at 55 the car was bouncing horribly.
Turning around I pulled the 2 rears off and found that one of those new tires (a Goodyear) was 4 ounces (NOT point 4) ouf of balance. (This led to an eventual free tire replacement because 4 ounces on a 195/60/15 is huge.)
She had been driving around for 2 weeks blissfully unaware that the rear end of her car was acting like a dribbled basketball.

The only reason I tend to lean away from tire balance is that the OP references acceleration and says it seems ok with no foot on the gas pedal. So it just sounds like its only upon acceleration rather than just always there at those speeds. To me a tire balance problem shouldn’t be affected by whether one is accelerating or not. Of course, further clarification would certainly help.

But the OP was also in the middle of a trip asking whether s/he should continue. I’d imagine that the deed is done - whatever it was and we may never know.