I’m with jdub on the issue of yanking the EGR: Pull it off with a stock ECU and you’re asking for a lean condition at part throttle (obviously a bad thing). When I was trying to track down the problems with the EGR setup on mine, I had Idunnohowmany friends from back in the days when I had my 5.0 Mustang telling me, “Just yank off the EGR. You don’t need it anyway.” I patiently tried to explain to them WHY I didn’t pull the EGR off my car (i.e. for the reasons jdub and others have said), but my explanations basically fell on deaf ears. Why? Because these were people who yanked every single bit of equipment off their cars that they possibility could, including the EGR and other emissions equipment, in an attempt to save weight and make the car faster. (I swear, I knew one guy who pulled the SUNVISORS out of his Mustang to save weight.) Regarding the emissions equipment, they said removing it made their cars faster, no matter how many times I told them that the emissions system shut down at full throttle and therefore wouldn’t make any difference in the car’s performance. Oh well. I’ve discovered that no matter how many times you give someone correct information-information that you can back up with hard data-people like that are ALWYS right, and you're ALWAYS wrong. Why? Because (they think) they know better. For those using EGR block off plates with a USDM ECU, and have had no problems with this setup, more power to you, I suppose, but it’s not something I’d do. I eventually stopped explaining to them my reason for keeping the EGR in technical terms, and simply told them it was because I have Obsessive-Compulsive Disorder (which I do), and otherwise the car would be “wrong” because it would be “incomplete”.
The JDM 7MGTEs had EGR block off plates because they had no EGR in the first place. The JDM ECU was tuned specifically to work without EGR. With a standalone EFI setup, you should be able to run without EGR because the standalone EFI setup is geared for performance; it doesn’t give a flying **** what you do as far as emissions is concerned.
Also, it may just be my OCD talking, but I’ve noticed a great number of 7Ms (madsupra’s included) running without the upper timing belt cover. While I know it would be an EXTREMELY remote possibility, but am I the only one paranoid about something-ANYTHING-falling into the timing belt area and causing problems? Not to thread jack or anything…I’m just saying that the possibility has crossed my mind…
Hope this helps…
Joe