When taking off if I punch it, it will take off to red line then drop down to 2000 rpms and whether i give it throttle or not it stays there. And it gets very monotone. Like the exhaust is rerouted from my loud set up o a factory system. I cannot figure it out, it will do it for a half mile or so then backfire extremely loud and take off from there. Any ideas, it has a new cat and EGR.

 

Was it doing this before the new cat? There might be an obstruction in your exhaust.

 

That i am nt sure I only had it a couple days when I had to put the cat on for emmisions.

 

o2 sensor is probably picking up too rich of a burn and leaning you out or vice versa either way it sounds like your cat is loading up with fuel then igniting

 

Hate to sound dumb but what would be the way to fix this? Like I said I just had the cat put in about 2 weeks ago. I drive a short distance to work I usually dont have this problem unless like las night I had to run home and back to work in a hurry.

 

drill a hole in front of the cat and see if it helps any then that iwll tell you if its the cat or not.

 

thats a lil extreme.



I would get a laser heat thermometer and test the cat out that way.
also when was the last time you did a tune up on it

 

dude if the cat is new and the o2 sensor is old your o2 sensor may not be getting the right readings now and you may want to find out if your truck is one that has 2 o2 sensors I know some of them did..

 

Ya know, when I was a kid, I used to say to my dad that it hurts when I do this - his response ALWAYS was "DUH, don't do this!"

So - don't punch it!

Oh - and if you put a new cat with a non-functioning O2 sensor - you could soon clog your cat! Best to address it quickly.

 

Cool guys I will get the O2 sensor replaced real quick just to make sure. As for the tune up I did wires and plugs about a week ago, but I still need to do the cap and rotor button.