random misfire on my 2005 chevy impala P0300 Chevrolet -

Question

Changed spark plugs and ignition coils (3) this flash lube place says its a air idle control
problem but does that cause bad starting,and stalling I just wanna be sure because before it was the sparkplugs then the coils and now this

Answer 1

P0300 Random misfire

Bad ignition coil or sparkplug will be confined to that one particular cylinder, If this is idle air control (IAC) it will cause low RPM which will result in stalling, but you would be able to bring up the RPM by slightly depressing the accelerator pedal.This would be a indication of a IAC. 4 component you need to be aware of, a slightly open EGR, a contaminated MAF (mass air flow) that is under reporting causing a lean condition,low fuel pressure, a faulty fuel pressure regulator. These are very quick test,If the engine is misfiring at idle, touch the EGR is its too hot to touch it is slighly open and a inspection will be required, For the fuel pressure regulator , pull the vacuum hose of the fuel regulator if fuel is coming out of the vacuum port of  the regulator, it  will need replacement, As for the MAF, do a MAF cleaning with a throttle body cleaning (which GM recommends) , alot of stalling at idle are usually cured with a MAF and throttle body cleaning,