I have a 05 equinox ls awd and when I start it half of the time when the engine starts the rpms go up to about 800 rpm but when coming back down the rpms dip below 500 and the engine starts to shutterbut then it returns to normal idling rpmsthe whole process only takes a few seconds but I cant figure out whats wrong.

 

if thats the only issue, you may have dirty injectors

 

I have the same problem. Sometimes I have to retry starting it several times before it starts. Intermittent regardless of temp/humidity etc.

Periodically getting Check Engine Light on... check code which reads P0171 system too lean bank 1 code.Perhaps the MAF sensor.

No noticiable performance change in the vehicle.

 

the MAFmeasure the amount of air passing by and adjusts the fuel accordingly, so dirty air filter or a K&N filter can cause the fuel delivery to be off causing either too much fuel, causing a first crank no start, second crank start conditionand poor fuel milage or not enough fuel causing stalling on the highway and a repeated no start condition with low idle...these issues can also be caused by water in fuel, fuel filter, ERG valve, air entering after the MAF, so check to make sure the boot is secure....some vehicles the PCM's need to be recalibrated.

 

Geezz, thanks for the info. I heard of issues w/ the K&N oiled filters... just using stock air filter. I will hafta check it in more detail. Running a scangauge to read codes.

How often should u change the fuel filter?