hey all, a little about me

2003 a4 1.8t quattro
apr stage 1
magnaflow exhaust
afe cold air intake
hyperboost dv

got the apr put on and hours later cel came on. read p0299. so i changed dv and shut off the cel. came back on hours later. then the next morning my cel was off? didnt come back on. so i thought maybe i fixed the problem. then sure enough last night came back on.

any thoughts

thanks in advance