This could be an airleak after the airflow meter, any expose dragged in here isn t seen by the ECU and correspondingly not compensated for and can lean the engine out and can as well as permit the engine to rev going on in the same way as not desired causing coarse running. As its a mechanical deformity it tends not to direction upon the irregularity lighthearted and you can sometimes listen a hissing noise when the engine running.
Its also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will every result in insufficient fuel subconscious delivered to the engine. Might also be worth cleaning out the idle enthusiasm manage motor / valve as these acquire clogged in the works past carbon and some brake cleaner washed through helps clear things off.
I don't have any check engine lights unless I unplug the MAF sensor. as soon as the MAF is plugged in next the car will stall unless I put my foot on the accelerator. There is furthermore an intermittent popping solid coming at idle.