I'm getting the engine SES light after i changed spark plugs, no matter how many times i resetted the ECU with TS procedures and disconnecting the battery. Should i bring it back to the dealer or bring it to some tunning shop for a diagnostic check? coz i think dealer will charge me anyways for checking.
I have mods like full exhaust and plenum spacer...should i take them off b4 bringing it to the dealer?

 

Go to autozone and get the codes pulled for free then post them up here. Without knowing the code its hard to make assumptions. Is it idling any different or misfiring. Make sure all the connectors are pushed all the way in on the coils.