will the blazer potentially throw codes if your check engine light isn't on? thus showing seemingly no issues? i had to replace my injector, though at the time, there was no engine light on. the vehicle would stall out, and the intake cover/ plenum cover(?) had pooled gasoline in the bottom, leaving me fairly confident the injector had failed, or the fpr could have been acting up.

in hindsight, should i have replaced the fpr while i was in there? or the map sensor?

the sucker has 414xxxkm on it, and it runs, from what i can tell, pretty well. still working out mpg.

does anyone run a thicker grade of oil on an older, more worn (400xxxkm) engine?

 

the injector would not throw any codes, as for the check engine light being off and codes being stored, I am not too sure.