92 camry bucking at around 40mph??

Do you do a lot of highway driving? Is the problem worse when you're almost out of gas? Does it go away in the winter?

I would suspect the transmission. If you haven't had the fluid changed in the last 20K miles, have a dealer do it and mention the problem. It might just be a simple adjustment. You can shop around at Toyota dealers for the best price, sometimes they have "coupon specials" for transmission service.

You might also turn off the over-drive switch and see if that makes a difference. If it does make a difference, tell the service writer when you get fluid changed.

Check your engine mounts are not buggered. These cars use a double sub-frame to insulate the cabin from engine noise and vibration. This also helps give that rubbery surging that occurs at certain speeds. Mine's a manual and it does it in 2nd gear with light throttle.

Jason

A long shot may be a vacuum leak. Listen to the engine very closely at idle for a sucking sound and slight dead miss. If so this is a rather painless fix.

Hi , what happend to the coil , did cleaning help or did you replace it,did it help. Your new problem sounds vacume system related, a leak or a bad device, just an idea, a good mechanic should be able to diagnose the problem with the right equipment. maybe fuel pump to. good luck youve had alot of problems