well my car has 80k miles on it and i had it dyno tuned a few weeks ago and my check engine light came on p0602 and p0300 he told me it may because of a few things maf sensor/ iac valve / front 02s/ and ect... i put a new iac on it got new plugs new air filter and cleaned the maf sensor im taking it back to him on sunday and i just want to make sure everything is working right when he retunes it ... i have cms stage 1 cams and just normal boltons
Actually on an untuned car 980 AD counts is pegged - most tunes, including canned tunes will extend that to 1023 AD counts which is analogous to 5v.
To check the MAF, log RPM, MAF volts or MAF AD counts, one of the airflow PIDS, usually #/min, load (which uses MAF input to calculate it). If all those seem normal, as in MAF volts/AD counts, airflow and load all go up with RPM when driving, the MAF is probably OK.