Hello all. New to the forum. I am now the owner of a Mustang. '07 V6 Supercharged with a ton of other mods. If I'm posting this in the wrong area, let me know. Ride only has around 38k. Was on the highway the other day and dropped to 4th to pass someone screwing around in the left lane and I heard the exhaust get louder than normal, then a loss of power. There's a lot of backfiring and loading up and I can not accelerate quickly and not get above 2000 rpm. If I have a light foot, I can still get up to 80 mph, but it sounds really rough. Had a half tank of fuel and filled it up and thought I got some bad gas. Then I did some research and thought it may be the TPS. Disconnected the battery negative terminal to clear the computer but no change. I then pulled the code last night and it came up P0405, EGR Valve. Would the EGR Valve cause this kind of issue? Sorry about being long winded for my 1st post. Glad to be a member.

 

Now that I'm trying to figure this out, I'm tuned so I think the EGR is turned off. If that's the case, what would cause this? TPS? Bad coil? Water in the fuel? Thx.

 

Would an EGR valve that somehow got stuck open cause this?

 

I guess that's a possibility if it wasn't turned off in the tune. I'll have to pull the paperwork out when I get home to see the tune settings. I got on it pretty good, but that's nothing I haven't done in the past.

 

The switch just flipped in my head. The car is tuned for 93 octane. When I filled up (already had a half tank) I wasn't thinking and put in 87 octane. Could that have caused the issue and if it did, what are the chances it damaged anything? I'm not used to pumping top shelf.

 

The tank has been drained, filled with 93 octane and retuned to 91 street and although it's better, it's not right. There's still a lot of hesitation, loading up and backfiring occasionally. The rpm's are up, but something's wrong. What plugs should I be running with a supercharger? I've read one heat range lower, but a tech at online chat said the NGK IX Iridium's with a heat range of 5 which is stock is fine. Which is correct?

 

So I found the insulation half blown off the #1 plug or so I thought. The wires in my car were numbered 1,2,3 starting at the front of the motor on the drivers side and not the passenger side like the manual shows. 4,5,6 should be on the drivers side. Here's the deal. It's been that way since the supercharger was installed and tuned, so do I follow the book or reinstall it the way it came off? I bought NGK Iridium plugs, Demon coil and Livewires. I'm thinking matching it to the way I pulled it off but not sure why #1 wire was installed in what is supposed to be the #4 cylinder.

 

SOLVED.