i just got my true dual flowmasters on but now my car feels like it shakes a little went im slowing down and when i put the car in park
is this normal? and i just have to get used to it or the muffler shop did something wrong?
thank you

 

Shakes?? Might be the rumble..take it back and have them check it out just in case

 

did you car rumbles a lot when you are stopping?

 

is it dumped under the car? also it could be vibrating on the body or tranny or crossmember

 

Make sure they didn't alter your cats or sensors. Even a burned sensor wire can make your car run like crap.

 

True, but that would throw a code and cause the CEL to light up

 

Not always. I had a damaged sensor wire and it didn't throw a code. But after Ford replace it, it got rid of my rough idle.

 

the car runs really good its just the vibrations behime my seat that ones that i think are kind of stronge specially if im using the A/C or heater.

 

Behind your seat if your using heat or A/C.... Thats puzzleing

I know i have to replace my alternator very quickly because its on its last leg, its causing an annoying noise as well you can hear how hurt it is when you turn anything on in the car.

 

Could it just be the exhaust resonating?