casperorr

I did a search for this problem, but found nothing. I really hope someone can help me.
I have a 2007 Mustang GT, automatic transmission, Saleen supercharger - 475 kit.
When I first start my car anytime of the day after it has set for a while, it is hard to get the darn thing to run down the road. It starts fine and idles fine and very smooth, but when I put it in drive and hit the gas it acts like it is choking out. It skips, sputters, and nearly dies out. I have to really feather the pedal to get it to move. It is very embarassing to be at the light or stop sign and when trying to take off it barely gets me across the street. I work and feather the gas pedal until it finally takes off. The best way I can explain it is that it acts like the old cold choke problems that you would get with the older carburator cars. It does it whether it is early morning when it is cold or middle of the day at 100 degrees. I had a Saleen supercharger installed, but I don't remember it ever doing this before. I have a 91 octane Brenspeed SC tune in it right now, so I called Brent and Dave and they said it could very well be that it just needs to warm up first. But I can drive it 5 or 6 blocks, and the whole time if I have to stop at a light or stop sign, it continues to have this problem for a while. After a few miles at running higher than idle, it stops. But like today I was at a car show and it sat for approximately 5 to 6 hours in the Arizona warm sun, and when I went to leave it was just as bad as in the morning.
I am not running any codes. Could this be due to the Saleen supercharger? I thought it might be the fuel pump, but wouldn't it act like this all the time and not just when it is started? I did notice that it seems to be getting worse. It is very embarassing, just making it across the intersection before it finally takes off.
Has anyone had this problem with their Mustang? My Mustang only has 11,000 miles on it. I will probably take it in to the dealership this next week, but I am sure that they will blame it on the supercharger right off.
Is there something simple I can do or replace before I take it in to the dealership? I don't know anyone in my area that has had this problem. Any help/advise that you can give me would be greatly appreciated.

Thank you,
Keith

casperorr

I came across this post while reading up on "automatic transmission shifting schedules". I believe it was "exx1976", that posted this in the other thread I was reading. He was saying that having hotter plugs installed during my Supercharger installation, that I would have rough idle until the plugs warmed up. I had the Saleen Supercharger and 475 kit installed. They installed hotter plugs and bigger injectors. So with what he was saying and that I did have hotter plugs installed,could thisvery well be my problem? I usually let the car run approximately 1 to 2 minutes before I take off and drive. Does it take a considerable amount of time to warm up before I should take off? I guess that I could do a trial and error test and letit idle and warm up a little longer and then if it continues, the next time I start her up I can add a little more time at idle, and continue this test until it stops rough idle.
So what is your opinion on this finding?Does anyone have the same opinion, or has anyone had this problem/issue yourself? I don't consider this a serious problem, but I just want to make sure this isnormal,but not let it continue in the event it is wrong and could possibly damage the engine, etc. etc.

Thank you all in advance,
Keith

sidmanic

You running Long Tube Headers?

casperorr

No. I am running stock. Other than the new SC and 475 kit and 4:10 gears, Brenspeed SC tune, it is stock. I did let it warm up today for about 5 minutes, and it did not skip, sputter, skip, like it was choking out except at my first stop that was about 1/2 block away. After that it ran fine. What do you think? Could it be that I need to let the larger plugs warm up as stated in the other message that I found?

Thanks
Keith

sidmanic

Mine hates being cold and it spits and sputters until it gets warmed up. Doesn't take long but its a normal thing.
Not sure about the plug thing, it could help but haven't tried anything. Just figure she's cold natured.

casperorr

Thank you for your help. I did try the warming up time before driving and it has solved the problem. I knew it was necessary for our older carb cars, but I didn't think we needed to do a warm up with our newer FI and SC systems.

Thanks
Keith

sidmanic

The reason I asked about the LT is because the location of the O2 sensors on some of the headers is too far back and they don't have enough time to heat up without the cats. This causes the Short term fuel trims to get out of wack and the engine runs like crap when it cold. This problem can be tuned out though.