Hello all i have a 2003 f150 supercrew 4.6. I started it up this morn and it rattled i have gutted pre cats so i thoght it was those rattling. but, When I got on the gas it would not go anywere so I Floored it. The check engine light came on after i got to 70 mph then it whent off when i got to 50mph so what do you guys think could this be my high flows pluged.

 

So you have a set of high flows and a set of gutted stock cats? If so, I really hope you got EVERY piece of catalyst out of those pre cats. If not, then chunks of it can and will remove them selfs and go directly down stream to the high flows and cause you problems. Gutting a cat is never a good idea, for a few reasons.

 

Yes sir i know it was a bad ideer to do that i was young and stupid haha. But it fixed its self so i do not know what happened.

 

It might have. I know that clogged cats will turn red hot after a while.

 

I remember when I took a steel pipe to the cat on my 97 grand am.

I tell you what though, for a 3.1L grand am with a bit of work done to it, it sure would run!

I miss that car, I had intake up from a 3.4L on it, straight pipe, a CAI I moved into the fender for colder air. I was about $500 short of adding a turbo from a wrecked 1991 "pontiac turbo grand prix" factory kit to boot!.

Ahh the old days.