Bad MPG? 2002 SS
 

Low mile (90k) 2002 SS falling short of the advertised MPG.

19 city 28 city is what is advertised, but Im only getting 15MPG with mixed city/highway driving.

It has always ran 93octane.

I drive conservatively (never over 2500rpm, try to stay under 2000rpm), and only occasionally give more than half throttle.

SS FI hoodscoop
SLP Lid
Kooks longtube headers
Offroad Y-pipe
3" Cutout in Y-pipe
(Stock muffler, No cats)

Its literally the cleanest LS1 ive ever seen. The engine bay is showroom quality, and it looks like the block has been regularly cleaned and polished.

I need troubleshooting help on the low MPGs...

Nice car. My ss gets at least 22 highway around 12 around town making noise. you should be getting better mpgs

Who advertised that? :)

I have gotten 29 mpg on a stock car, traveling 55 on a flat interstate right after a carbon cleaning and with new fuel injectors. It gets worse from there.

If you add hills and travel over 55 mph, the mileage gets much worse. At 75+ mph, I've never beat 24 mpg on the highway. 15 mpg for mixed usage on fast highways is pretty good - IMO. For some city driving, (in a real big city) I get below 12 mpg.


The best way to really tell if something is wrong is to fill up and go for a highway drive at 55 mph. Then fill up and calculate your mileage. That will give you a good benchmark to measure against. High speed driving on the highway and mixed driving doesn't give you very useful data points.

BTW - If you are in a cold area, you are on winter gas right now, which doesn't help. I did the math a while back and recall that the increased ethanol content will drop you by one-ish mpg.

I was having a similar issue with mine and I changed the o2's, fuel filter, and injector seals while I had them out and one of the three did the trick.

If you don't have a tune with those mods your MPG's could suffer.

advertised MPG is in ideal conditions. no one drives in ideal conditions.
winter gas doesnt help MPG
dirty air filter doesnt help MPG
running rich from header install with no tune doesnt help MPG

For some reason, expensive gas also seems to make the mileage worse, somehow...

LOL, never heard that one. Who knows...

I've put Walmart gas in my daily a few times and dropped 3 MPG. This was just regular 87. Didn't change my driving style or where I drive. Next fill up with Shell or Chevron/Exxon 87 and instantly get my normal gas mileage. This wasn't just once...It's EVERY time I've gotten garbage. Never again :mad: I'd done the same test with my TA with 93 octane and same shit, so its not just 1 of my cars.