My '67 Convertible just developed a strange problem. It has run fine,
absolutely wonderful, for days. I drove it to work this morning and it
performed perfectly. I had to run an errand at lunch and went out to
start the car. It started fine, but the exhaust sounded ever so slightly
"muffled". Idle was fine, so I put it in gear and went on my way.
Acceleraton didn't feel right, it was as if I was pulling a trailer. I
stopped at a stop sign and then pressed the gas to go and a big plume of black
smoke came out of the tail pile. I let off the gas and noticed that a
slight trail of back smoke continued. The further on the pedal that I
pressed down, the more smoke I got.. and now the performance went downhill
fast. I had to press the pedal down twice as far as usual, resulting in
black smoke just to drive 35 mph. I had only driven 2 miles from work
and now could barely top 25 mph with the pedal nearly to the floor... black
smoke just gushing out the back end. I pulled over and put the car in
park. Black smoke dropped to almost nothing and I peaked under the
hood. The engine was idling perfectly. Smooth and no misses
whatsoever. I blipped the throttle cable and the engine revved smoothly,
but more black smoke out the tailpipe.
So, the engine seems to be running fine, but black smoke gets worse as I
accellerate. Car seems to have no power while in drive. Engine revs and
transmission does not slip. I backed the car up into a parking spot and
scratched my head a bit. Walked around to the back end of the car and
the exhaust does sound a bit muffled still. It also left a black patch
on the grass just while idling. I rubbed the grass between my fingers
and it was sooty, no real fuel smell. No grey smoke, no steam, so probably not
rings or a head gasket. What on earth is going on here? My guess
was a clogged exhaust, but then it probably would have blown that sucker right
off the car when I revved it a couple of times, now wouldn't it? Could
it be a pvc valve? Does the '67 440 have a pvc valve? HELP!
Thanks.