Just picked up a '92 with 3.9 V6 and AT. This thing is getting horrible mileage (12-15mpg at best). The exhaust was new when I bought it and has been a little on the loud side (compared to my '94 4x4 with same motor/tranny combo) but at the same time it sounds a little restricted. I crawled under to take a look and I noticed the muffler has arrows pointing in both directions with a 4 on the input side of the arrow and an 8 on the output side. Anyone have any ideas on whether there is an issue here?

Thanks!

 

The muffler probably is not stock that is why it is louder then stock. Even with the V6 you may not get much better than that MPG. As far as your arrows I have no idea what your talking about. But go to a muffler shop and ask if they can take a look.

 

I think its just a reversible muffler for various applications. Like the Thrush Turbos, Welded, etc. I think theyre an A and B, not 4 and 8, just to symbolise which inlet/outlet is which. I'm assuming the A pipe is closer to the inside of the truck and the B pipe is towards the outside, offset from each other, right?