you dont need to get to your ecu to run a diagnostics, just the little port above the Hood
latch release. you plug a scanner to that to run the code check. go to an autozone and they will check it for free.
if its your Intake
, check your vacuum lines, you may have crossed them. clean your MAF.
if it comes to your gas tank, make sure it clicks a couple of time when you put it back on. then, unplug the negative from the battery and let it sit for 10 min then plug it back to to reset it.
otherwise, just do a scan.