Originally Posted by Biscuit

I just got my 89 Sentra back on the road for the first time in 7 months. I put a full tank in her at the station down the road and 3 days later I done knocked it out and I had only been 250 miles and I filled it up again with some better gas and shes still getting the same mileage. Before I parked it I was hittin low 30's with my foot in the throttle body. Im driving her easy now and I dont get it. I know its running rich because of the black smoke that comes out the pipes when I rev it up a little. I still have good power and throttle response. Other than the thermostat being messed up it runs like a champ. Speaking of that the new thermostat makes the engine run too cold. I also took the cat off and now I run a glasspack with dual side pipes. So I dont know if taking the cat off is making all this happen. It should get better mpg since the exhaust is freer flowing. This car used to maintain 35-38 mpg when I first started driving it and it has slowly went down. The EGR checks out pretty good because I can make the diapragm go up and down with little effort. I found that a sensor on the intake was disconnected and I hooked it back up. The backfiring when gearing down went a away some but it still does it...and we are talking foot long flames coming out of the pipes. It looks cool but I know its not supposed to do that.