Engine Mechanical problem
1995 Chevy Tahoe V8 Four Wheel Drive Automatic 120000 miles
Tahoe only used to tow a bassboat; slight blue smoke for past 6 months; very infrequent use; moved boat 6 feet; turned engine off; tried to restart and felt slight " bump" from under hood; engine would not restart; had it towed to shop; getting gas, but seemed to be fault somewhere in ignition system; mechanic recommended full tune up; replace wires, plugs, distributor cap, etc. Engine starts but very rough; smoke, from exhaust; incomplete combustion. Checking timing at moment. Any thoughts?