Ok, so ive had my truck for 18 months now, and ive had no muffler for about 16 months now. My exhuast ended after the CAT.

Well i just put on a Cherry Bomb turbo exhaust, and the truck runs MUCH better with a muffler. But now i can really hear my CAT rattling...i know it needs to be hollowed. Also my egr pipe is cut on each end, and have bolts welded into the pipe to prevent an exhaust leak.


SO...i have 207K on the truck, and she runs beautiful, but i noticed my mpgs are kinda taking a hit somehow....im getting around 8-9 mpgs city, when i use to have around 13-14 city last summer...this winter is when it took its hit, but its been 50*+ and the mpgs are still low. But whats weird is my highway mpgs....i went to drop off a buddy (218 mile round trip) on less than a half a tank of gas and it was ALL highway but 2 miles...whats up with that? to much of a difference....and im not hard driving the truck around the city at all.


Now for a couple more questions.

I figure my 02 sensor needs to be changed...since i did my plenum at 195K, and i have the original CAT and 02 sensor, so i know its getting a wack ready due to carbon build up.

Now will the truck pull its own code if the 02 sensor is bad? I very rarely get a CEL with code 12, and 32.....one of which says my EGR gases not functioning properly, which i believe is due to my egr pipe being blocked, ( other code is for battery being disconnected within the past 50 key cycles) and i still have the egr valve hooked up.

And does that EGR pipe play a role with the 02 sensor? will the egr pipe effect the mpgs?

and if i hollow the cat, is it worth getting a new 02?


Thanks for the help in advance....im not really worried about gas mpgs, but since the egr pipe (already have) and hollowing the CAT wont take any money, i figure its worth getting those mpgs back.

 

i say get a highflow you would like that alot better than gutting it out. and then get new o2 for a good clear reading.

you could hollow it out for now see how you like it , and go from there .