Could be a possible vacuum leak in the fuel intake system? Could also be premature kickdown out of overdrive at a certain speed (if your truck is so equipped.)
replace the catalytic converter
A computer tower may make a surging noise rather than a constant humming noise if the case's screws are not properly tightened. Another reason for such a surging noise is the imminent failure of a fan.
Fuel pump could be possibly getting weak. Happened to my blazer.
try changing the petrol filter
Bad brake booster.
A defective catalytic converter can do that.
There are several things that can cause your 1995 Chevrolet Blazer to shake when accelerating. Bad spark plugs and spark plug wires can cause the vehicle to shake. Tuning up the engine may eliminate the problem.
might be a fuse
Head gasket or cracked head. Mo
A faulty alternator, a faulty belt tensioner.
A dirty or clogged air filter would cause excessive fuel consumption, and it could cause the engine to surge, but I'm not sure about the drop in your alternator guage.
A broken timing chain is a possibility.