Ok i decided to do what people said would be cool and i took off my muffler and replaced it with a straight pipe. The problem now is that i get an awful vibration up until 2000 rpms then it smooths out. I didnt notice it before i had the exhaust worked on. When i was driving down the freeway my check engine light started flashing then it just stoped. I did have problems with a bad coil on a spark plug at one time and when i replaced it it was fine. I dotn know if another coil is going bad or what i feared most that now my 5.4 has no back pressure and now has no low end torque. Any help would be great.

ben

 

check your o2 sensor might be lose , maybe when you did work on the exhaust ???

 

check light flashing means you have a misfire accuring. and that could cause big time lack of power and vibrations.

now after you get that fixed if it still vibrates you might need to strap some weight to the pipes to take the resonance out of them. kind of acts like a dampner.

 

hi blue..i feel the pain of the man that sold you this truck,and yours as well..my truck had less than 40k when mine started though...here is the link to my missfire/vibration? thread https://www.f150online.com/forums/sh...hreadid=186797 if you find out what is causing all the comotion please let me know..and i will do the same fro you..this sure is one big mystery and a very expensive minor problem that might be impossible to track down...good luck

 

Go to autozone and get your codes read.