I just recently put on some pacesetter long tubes connected to a true dual 3'' system with a magnaflow X-pipe and two magnaflow mufflers(6'' can) and I have noticed that i have been getting significantly worse gas mileage! is it because i am driving faster which I’m really not or has this happened to any one else? and my fuel gage is going crazy too, some times it sticks and some times it just totally drops to empty.

 

Just a question but have you gotten a custom tune to go with your long tubes, its almost necessary with long tubes to get a new tune for them to act right.

Also, not trying to box your ears or anything, but man, a true dual, 3" system? Thats a bit overkill, are you all motor or running forced induction. With a true dual setup, 2.5" is really all you need for motor. Are ya running cats?

 

IMO your foot has gotten heavy. You should gain without a tune but the big *** exhaust is killing your bottom end Im sure. Honestly I think you are putting your foot in it more its only natural.

 

Very true, Heavy foot disease will do it every time.

 

on this one.

Those two 3" pipes are way overkill. You basically killed any back-pressure that your engine needs for everyday driving. The back pressure gives you your throttle response and low-end TQ. You should never over due your exhaust system unless your about to install FI (forced induction) ie; turbo or S/C.
You will definately need your truck tuned for what you have done so far. Your mpg's may go up from just the tune. Though unless you go S/C'ed, turbo, or down size your exhaust pipes, your mpg will suffer. Not a good thing with current & future gas prices.
Good Luck!

 

im not really shure about your gas mileage, but as far as your gas gage going crazy it is probaly the fuel sending unit. mine did the same thing and the only way to fix it is to drop the gas tank and replace the fuel pump and gas sending unit.

 

I thought it had been determined that you can replace JUST the sending unit to fix this problem. Is that not still true?

 

You're right. Replacing just the sending unit will solve the erratic gas guage problems. There's no need to replace the whole assembly.

 

I'm not running cats and i have not yet gotten a tune, the guy that does my tunes is on vacation. I thought the same thing about my low end tq but i dont really feel it that much diff if anything its still better that stock. as for my motor i am going to do a blower setup in a few month but nothing yet. and i checked my foot and it had gone up a few Lb's but i put it on a diet!

 

I agree....

Also removing your cats often requires re tuning in itself so you have made some major changes to the exhaust flow and possibly chamber scavanging ability of your engine so defiantely get it tuned when the guy gets back and let us know how it goes