help me my car is goin crazy..i changed the wires plugs cap and rotor and it still does the same thing..in the mourning when i start it up the idle starts goin up nad down like the car is seriously misfiring and when i try rev to higher it sumtimes backfires..also when its in load "d" or "R" the engine rpm sometime go below 500 and feels like it wants to stall at a stop light wen that occurs i put it in neutral and the rpm goes up but slowly does teh same thing again..my check engine light always blinks when this occurs especially in the mourning wen trying to warm up..the codes are p0300-p03004 misfire codes..i need ur help i dunno what else to check im thinking the iacv but how do i check if thats working help me please

 

ej? what year car dude?
clean your iacv and ficv. check the coolant level.
see if any sensors came unplugged

 

You said in the morning the idle bounces, does it ever idle ok? Have you ever messed with the TPS? When did this start? First check all of your grounds- the strap from the battery negative, the thermostat ground and the valve cover ground. Replace your air and/or fuel filters and PCV valve if they haven't been replaced in awhile. Check the MAP sensor voltage, preferably at normal idle. Write down the output voltage and the RPM you are at. Either carefully check your spark at each wire with a new plug or have your coil tested. If none of that uncovers the problem, get a loaner fuel gauge from an auto parts store and test your fuel pressure.

 

You could have air bubbles in your coolant. That will also cause an idle to bounce. When your engine is cold take off the radiator cap and let the engine run until it is warm. Then put the cap back on. That should get all the bubbles out if there are any.

You might have a vacuum leak somewhere.....start the engine and take brake cleaner or starter fluid and spray in little areas at different times where the TB is, then the IAC, the map sensor, and then all the hoses on the intake manifold. Really anywhere there is a seal between 2 different things. Dont spray all areas at once, one spot at a time. If your engine revs when you spray that area youve got a leak. Try replacing gaskets or clamps and hoses.

Hope you figure it out.

 

this is from 5 months ago man.