Hiya guys.
Well I think I posted something about this awhile back and thought I may have had a fix thinking it was my clutch but I have since decided against that and am having worse issues so I’m kinda at a loss.
I have a 2006 gt with a Paxton kit from brenspeed. Ran fine for a few months then started getting an engine code for a bad coil on #3. Cleared the code and it came back a couple weeks later. Cleared it again and another couple weeks later it came back so I replaced the coil. Hasn’t come back yet but has only been a few days.
Also the car idles steady, but it shakes the whole car. Didn’t use to do that. It sounds strange too. The exhaust note has become a bit lower pitched and lost its growly sound. Very odd. I also can’t be completely sure but I feel like I may be slightly down on power. That may just be the stumbling though.
But my main issue is that the car seems to stumble at low rpm. Sometimes at higher rpm too. But usually under 3k. It feels like it’s missing. Almost like I went over a bump or something. I’m not sure how to explain it. It isn’t surging. And the tach reads steady. It does it randomly while cruising, maybe every couple seconds. And it is completely repeatable under acceleration while at low rpm. Every time.
Other than the coil code I have no other codes. As far as I can tell there is no vacuum leak, and my boost-a-pump is working as it should. Replacing the rest of the coils or maybe replacing the fuel pump are the only other things I can think of to do. Otherwise I figure it’s time to take it to somebody unless o be of you guys can help me out. It’s be great if ya could.
Thanks

 

If you're still getting the cylinder 3 misfire code, switch the coil around with cylinder 2. Clear the code and if a code reappears but it's moved to cylinder 2, you've found the culprit and you can replace the coil. If the cylinder 3 code persists, try switching the spark plugs and if that doesn't work, try the injectors.

 

Ok. If it comes back I will switch them and try that. Maybe I’ll go ahead and change my plugs too. They don’t have even 5k miles on them yet but maybe.

 

2200 or 1200 Paxton kit?
Is it currently tuned by Brenspeed?
What position is your MAF clocked at?

 

It’s a 1200sl. Yes. It has a brenspeed tune. And my maf is pointing down

 

If it helps it ran great for 3k miles after I installed the blower. I got into a minor wreck then and all that was repaired was body. Afterwards it still ran perfectly fine for about 3 weeks then started doing this

 

What plugs are you using and have you looked at them? If switching the coils around doesn't help solve/narrow down the problem, it wouldn't hurt to change the plugs, especially if it has been misfiring. Have you done any data-logging? That could help narrow down the problem as well. The Brenspeed tune is a "one size fits all" type of tune, and my 2200SL didn't have great driveability when I ran their tune. (It felt like it was missing at lower RPMs and felt sluggish) Depending on your goals with the car, it might be worth it to switch to a blow-through design and tune with Lito.

 

I am using the plugs brenspeed sent with the supercharger. I can’t remember for sure but I am almost positive they are ngk iridium plugs. Having said that I ordered some Autolite ht0 plugs last night. I checked the plugs with my spark tester and they seem a little off. Hopefully that is my issue. Next I will try coils. If that doesn’t work I will probably take the car to someone. Unfortunately there aren’t very many shops around Oklahoma City that will work on modified mustangs.

 

Sounds like you're headed in the right direction. Don't get discouraged, good luck, and keep us posted!

 

Yes. I will do so.
I will replace the plugs and maybe coils. The only other thing I can think is to open up the wiring harness and make sure my lines are ok. When I installed the blower I accidentally left the negative terminal connected and drained the battery. Had to get a new one. When I connected the positive it had cracked and it caught fire lol. I’ll check that