YES, I have experience that b4 and it cause me not to get to work that morning. I'm the type of person who will find out what the problem is b4 it gets fatal instead of letting it blow up and finding out what happened afterrward.
Turned out to be nothing in the engine or rear end, just
BAD U-JOINTS, but it does feel like it'd be coming from the engine (I thought at first it was my harmonic balancer). I'd suggest removing your driveshaft. If you have ramps, then it should only take ~ 30 minutes (that's unless you have serious problems removing the 4 bolts that connect the driveshaft to the diff.
Anyways, remove driveshaft and check front and rear joints. If they're bad, you can use it as an excuse to buy an Al driveshaft or just replace u-joints for about 15 bucks, an easy repair.
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351W-powered 1979 Ford Mustang notchback
Stock 5.8L under 4" cowl, C4 w/ shift kit
Holley 750 cfm, Edelbrock Performer RPM intake
1 5/8" MAC shorty headers, Al driveshaft
2.5" Off road H-pipe, 2-chamber Flowmasters
Front: 225/60/15, Rear: 255/60/15 Eagle GT II
Weld wheels (15x6;15x8), 8.8" Rear w/ 3.55s
14 x 4” K&N air filter (getting the Xtreme setup someday)
"Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body
[This message has been edited by Fox Body (edited 08-17-2001).]