Hellow i changed spark plugs " gas filter . and the motor keeps on shaking. rpm shows less than 1000 rpm how to adjust the rpm ???? please help thank you very much

The first thing i would od here is to go to an atuo parts stor and have the computer scanned to see if there are any stored codes that may help in finding the problem. the computer will store a code when it sees the engine not operating they way it should. there are many auto part stores that scan for free and give you the codes.

If this was caused by a misfire due to a bad coil then the computer should of turnned on the check engine light. try cleaning the throthlebody with a toth brush and some throtlebody cleaner, this sounds like the idle is not being controlled to specs. it is lower than normal. this may be caused by a dirty throtlebody or bad idle air control valve.

Take a look around and with the engine running check for any vacuum leaks, sometimes depending on how bad a leak you will hear a hissing sound, check lines for any splits or cracks. it common on the rear of the intake manifold. hope this helps.