Hi all,
I got a few things going on that could actually be multiple issues, but all happening over the last 1/3 tank of gas. The only thing I did differently was vacuum out the air filter a bit... I know that's a bit of a no-no, but it was really dirty and I couldn't wait a couple of weeks for my K&N (I know, another can of worms) to arrive in the mail. And I was careful about the vacuuming, only really going after the big stuff (leaves, feathers, etc.).
Since then, I've had a three things happen. First, the fuel economy went through the roof. I've been running consistently at an average of 33 MPG for the last 5 fill-ups (roughly 50% city, 50% highway). However, I could tell that the needle was hardly moving the last few days. After using about a quarter tank, I had gone just over 300 km ~ 190 miles.
During this time, the check engine light also came on. I found a P0451 code (Evaporative Emission Control System Pressure Sensor/Switch Range/Performance). I reseated the gas cap, and cleared the code. It hasn't come back yet. However, after taking the car out about 5 times, the EVAP monitor, catalyst monitor and EGR monitors have yet to run their programs (the others HAVE).
Concerned that my car was running lean, I went to fill up today to see if was just the fuel gauge going wonky. However, the gas station pump kept shutting off, right from the start. This has happened to me a few times in the past, and seems to be a common problem on the 2000, as documented here:
http://www.suzuki-forums.com/suzuki-...-fill-ups.html. So I couldn't really tell when my tank was full, but the needle ended up being pretty much where it is after a fill-up. And my gas mileage came out to 41.6 MPG (compared to the usual 33)! I realize that there is some variability, especially due to the pump shutting off, but I don't think it would account for an improvement of 26%.
So here are my questions:
1) Can vacuuming out the big debris from the air filter lead to such a dramatic improvement in fuel economy, up to 42 MPG (50/50 city/highway)?!
2) If not, can I be running lean without the oxygen sensor monitor detecting/reporting it
3) I realize that the problem causing the gas station pump to shut off could be tripping the P0451 code. Could it also be causing my gas needle/fuel level sending unit to read inaccurately?
Thanks for bearing with me
