I would suspect a vacuum leak. Replace or repair all vacuum hoses under the hood.
But before you do that (that could be very Costly) spend the the money and have a Diagnostic Test done 9 out 10 times it will pin point the problem.
Engine hard to start, rough idle, fouled plugs, fuel in oil, poor gas mileage
Poor fuel miliage, rough idle, no start, poor acceleration, stalling.
I am having the same problem, and poor acceleration!!
One of the symptoms of a bad boil pack is a rough idle. Other symptoms include a loud engine, loss of power, and a check engine light that goes on and off.
A miss, black smoke and a strong gas smell. Also, bad acceleration, rough idling, and stalling.
The symptoms of a 4.3 liter V-6 engine timing chain problem is an engine that runs very rough. The engine will shake violently.
On most vehicles, a bad o2 will cause the chech engine light to come on, decrease in fuel mileage, and varioius runing problems including: surging, running rough, stumbling.....
black exhaust,rough idle, miss in engine,rough operation of vehicle lower performance,higher fuel consupmtion
With a bad/burned intake valve the engine will idle rough with a skip and lose power. The cylinder in question will test low in compression. If the valve is damaged bad enough the engine will make a popping noise through the carburetor or throttle body especially during acceleration.
Check the EGR vavle
Check engine light, rough running engine, no start at all.
Engine running real RICH / To much fuel. Smokeing black out of the exhaust engine running ROUGH.