Hi guys, I've had my 2001 Monte Carlo SS for a little over a year now and finally got curious and tried to record my own fuel economy/usage and compare it with the overhead trip computer's. I was shocked when I calculated it myself (just dividing distance traveled by the amount of gas needed to fill my tank) and found it to be just 18 miles per gallon compared to the trip computer telling me that it was 24. Is this a common/known issue with these cars or can I do something to correct this? (At least make it accurate, even though it's not good fuel economy) A little background info that might help: I replaced the fuel injectors and fuel pressure regulator shortly after buying the car to fix an issue where the engine would flood after shutting off and be difficult to start for a few hours. (The fuel injectors didn't solve the problem, the regulator did) Also it's been pretty chilly these past few weeks where I live so the car probably spent about an hour total warming up during that whole measuring cycle.

 

Hello Chris, Mine is off too. Not as much as yours, but off just the same. Also, my instant MPG only shows "E". I have an 02 SS that I have been restoring for the last 2 years. This question and others regarding the overhead readout have been posed before. I don't think there has been an answer. But there many Montes that have problems with it. I personally only use the Temperature / Compass. They seem to work just fine. My Fuel Used always says I've used 10.7 gallons or So but my gas receipts say I've gotten 13 or 14 gallons.
Maybe someone knows and just hasn't read any of these Post? I don't know. But I have not come across an answer. Sorry!

 

JC, have you checked tire pressure? Clean out your o2 sensor & MAF. Running any mods? Exhaust mods? Sometimes if you run too many mods, you may need a tune to fix your computer settings. Imo, d/c the battery, clean your sensors and air filter for your throttle, then reconnect. Try testing your MAF by disconnecting it when the car is on, if it runs the same, your maf is bad, if it runs rough, such as idling hard, then your maf is good. If you d/c and it it starts to run hard, but then goes back to running the same, its going bad. Try cleaning it with spray first bro and see if that helps

 

Mine is off as well it says like 20mpg but I get around 15-16 No one's knows a sure fix for this

 

Oh my...well i mean two diff gens of montes between mine and you guys..so...didnt know 6th gen really had that much of an issue with it.

 

Hiroska, I just got a new Delco MAS 2 weeks ago. All the other sensors were replaced in July. The only mods I have is a Magnaflow CAT and o big rust hole in my resonator, which I plan to steight pipe next month. The thing has been off since I got the car in April 2012. It's not really important but I figure it has something to do with everything that is wrong with the car. Like the TCC. (Also replacing next month). MY O2's may be original. Working on replacing them by the end of this month. YellaJAC is due for NJ state inspection in Apr. So I'm trying to Ger these last few things done. So the D.I.D. is still not on top of my list but it will be.