HipHotRod.....

I talked with a couple of "friends" about your lack of MPG. After providing them with many of the solutions that you tried, here is what they suggested.....

Use the MPG indicator on the DIC. Fill your tank and watch that indicator AND the RPM gauge. IF you drive mostly city with a lot of stop and go, DO NOT EXCEED 3000 RPM (especially in the first 2 gears). At about 2700 RPM is when the VVT "kicks in", thus using more fuel.

When the MPG indicator is initially set to zero, it is more sensitive and reactionary to driving habits and should give you an idea of your fuel useage for each situation.....stopping at a traffic signal, different speeds etc.

One question I was asked that I couldn't answer.......in your normal stop and go driving is there enough distance/time to allow the vehicle to get into 4th gear??

Give it a try and hope this helps.

 

NEVER going to flash mine. I am perfectly happy with my gas mileage, and as for "proper break in", The day I picked mine up, I drove it like it was stolen and I am at 53K. I firmly believe if you dont break it in the way you drive it, then it will not perform up to your satisfaction. Same reason why I would never own a used vehicle that "a little old lady" owned. Just my two..

 

Hey Snoop, Thanks. I will look into where my RPMs are. I am almost certain that I keep the rev's down unless I am passing someone or starting up what little grades we have here in Long Beach. Yes the car gets into 4th gear more often than not. I also have just noticed there is slightly oily soot in my tailpipe. This would seem to me that the car is running rich. ChevyMgr and I have been emailing back and forth about this. Although it has not thrown a SES code yet, I am leaning towards whatever is causing it to rich out is on the threshold of rendering a code. What I might do is to unplug a sensor to make sure the SES is working prior to going to the dealer to have it reset.

Tireman, I drove with the whip effect for almost 1000 miles when it was brand new. I didnt baby it nor did I banzai it harshly. Other than the mileage issue, the car runs great. I am wanting a reflash to eliminate that as the cause once and for all.

 

This is going to be some component in the fuel mixture management end of the spectrum in your scenario, hiphotrod. That mpg is way too low and with only 2000 miles I would not expect to see much if any carbon build-up on the exhaust tip yet. You're correct in that excessive carbon build-up on the tip can be an indication of the mixture being too rich. You're also correct that it is likely going to take a technician who understands the equation and has the time and desire to roll up his (or her) sleeves and get into it, what you don't want to be stuck with is one of the code reader and parts changer type of techs who doesn't have the passion and the knowledge.

One trick to also check for the mixture being too rich is take an oil sample and send it to a lab for analysis. Granted, YOU shouldn't have to do that, the shop should, but the analysis can detect the level of fuel dilution in the oil-- there are normal average baselines for engine type and the mileage on the oil, engine age, etc., that the lab can compare the resulsts of your oil analysis with to determine if the level of fuel dilution present in your sample is within expected norms or excessive. The lab would also consider season and avg OAT (Outside Air Temp) as operation in a cold/cool climate would need to be considered so the results of your sample could be intepretted correctly for the weather conditions the engine was used under.

 

I was getting in the upper 20's with my 07 and after I got a dealer oil change, it seem like my mileage dropped. So maybe at the dealer they use bulk oil and maybe one size fits all. Also winter was just starting so maybe the weather has some effect on the MPG. I'm at 60 percent on my oil change and I'm going to wait till it hits the 50 percent mark. I'll be putting some Valvoline 5w 30 and Ill see whats happens to the MPG

 

If you want the best mpg oil, full synthetic is usually the best way to go.

 

Thats on my list as well. I ordered the KN a/f on the 1st of april and it hasnt gotten here yet. Sucker wont return my emails and there is no provision to call and leave a message. Im going to run either royal purple or Mobil one in the car when I give it its 1st oil change.

 

I used to be a die hard Mobil 1 fanboy, but not so much anymore. There are many other choices now. I have 6 qts of Q-Horsepower 5W30 in my garage that I got free after rebates ($15 from SOPUS, $15 from Pep Boys) last year that I'm going to put in after I get 4000 miles out of the Mobil Clean 5000 currently in the crankcase. From then on it will likely be Q-Horsepower all the time for mine, at which point I will be able to place more trust in the OLM (Oil Life Monitor) on the HHR's DIC due to having less qualms about running a synthetic that long vs. a conventional. I don't buy into the "more horsepower from oil" hype that Q is pushing-- just that Q is a very good synth and I have a lot of faith in SOPUS products.

 

That would be me, I'm one with an 07 panel and get 22-25 in town and 29+ freeways...oh and I have LOTS of hills.

curtsy
Elle'

 

Today, driving around FLAT, no hills Long beach, averaging 15.7 MPG and driving under 3000 rpms. Can easily see the black crap in my exhaust tip. It IS running rich although no codes have been rendered. I need a GOOD Gm tech.