IPD plenum still puts CEL on HELP!

[Topless]

Yep. Sounds like a completely fouled or disconnected MAF. Pull it out, give it a good look, clean it if needed, inspect the plug in connections to make sure it is seated properly. Also trace the wire harness to make sure it did not get damaged or pinched during your intake mods. This should be an easy fix if you take your time and follow a process of elimination.

FYI: disconnecting the battery will always turn off the CEL and erase the error codes but it doesn't erase the problem that is causing the codes.

[thom4782]

Some monitoring systems don't carry out tests until the car has gone through a number of cycles - starting, etc. - after you clear the codes and lights. Then after the right number of cycles, the system starts testing again and the CEL will pop back on if the problem wasn't fixed. It's not clear - at least to me - what these cycles actually are, but that's why it seems so arbitrary when the CEL comes back on. Good luck in finding the root cause of the problem.

[Johnny Danger]

What source did you purchase the sensor from ?