MAF sensor

'94 4.6l seems to run better with the MAF unplugged, why?

because your maf is either bad or incorrect calibration for vehicle when you unplug computer compensates by using known good default (limp home mode) since maf is only thing missing comp knows baselines for fuel curve

It finally got bad enough to set the check engine light, will be headed for Autozone to get some code info. Think maybe the EGR is sticking. The idle keeps jumping up around 1400, more so when the AC is on, causing a loud roar thru the intake when it goes high.

Ended up cleaning the EGR ports under the upper plenum and replacing the IAC. Added K&N intake filter and removed both rear mufflers. Runs much better but did not quite get the sound I was looking for.