I have an '87 Firebird 5.0 and I have a problem with vibration through the car (not the steering wheel) at 60mph+.
I was originally told that this was due to 2 of my wheels being buckled, so I bought a set of 2nd hand Transam wheels & tyres (these are slightly wider than the original set).
I had the new wheels fitted & balanced (they look awesome!), but was told that one if the tyres had a sght "flat spot" presumably where it had been stood around whilst fitted to the previous car. This tyre is fitted to one of the front wheels.
Now, when I am on the motorway (I live in the UK), I still get a vibration when travelling 60mph or faster. I've had it up to 85, and the vibration is still there, doesn't seem to get any worse or better, just different frequency.
can anyone tell me whether this is likely to be the tyres, or is it more likely to be the propshaft, or a halfshaft that are bent or out of balance, seeing as how I've had the wheels balanced? I can't really afford to buy a new set of tyres just to see what difference it makes - I got into enough trouble for buying the wheels!
Any advice would be appreciated as this is spoiling an otherwise good car.
Andy