MPG lessening quickly!?!?!

[smarrs12]

So a few weeks ago I went in for an oil change, and now my mpg is getting less and less. When I went in for the oil change, I was like 1900 miles over the routine oil change (Normally I get them on time, this past couple months I have been super busy).... So the mechanic says that because I am so far over I should get a cleaning, conditioning treatment, that would remove "sludge." He says that this treatment is put in, then the car in ran for a few minutes, and then emptied out. So I did that. Then he also had me replace the air filter and cabin filter; bought new, and had him put in.

But now I am getting near 50 miles less per tank. I always fill back up when I am down to a 1/4 tank gas, and normally I got 260 miles. Since this oil change day, I am not getting more than 210 before I am back to a quarter tank.

What could be going on??

 

[BankDude]

put some injector cleaner in your gas tank and replace your plugs

 

[Bass_Waves]

Seafoam?

I sent this thru the Intranet™

 

[Tuner923]

So a few weeks ago I went in for an oil change, and now my mpg is getting less and less. When I went in for the oil change, I was like 1900 miles over the routine oil change (Normally I get them on time, this past couple months I have been super busy).... So the mechanic says that because I am so far over I should get a cleaning, conditioning treatment, that would remove "sludge." He says that this treatment is put in, then the car in ran for a few minutes, and then emptied out. So I did that. Then he also had me replace the air filter and cabin filter; bought new, and had him put in.

But now I am getting near 50 miles less per tank. I always fill back up when I am down to a 1/4 tank gas, and normally I got 260 miles. Since this oil change day, I am not getting more than 210 before I am back to a quarter tank.

What could be going on??

this is a fucking rip off!!!!! oils have detergents in them. change your oil next oil change on time and you'll be fine. this is one of my biggest pet peaves. scam ass hack job grease monkeys. full synthetic can go to 7,500mi without change, to 11k with testing first at 7.5k



---------- Post added at 02:34 AM ---------- Previous post was at 02:31 AM ----------

put some injector cleaner in your gas tank and replace your plugs

this does absolutly nothing btw, its all placebo. gas tank bs is so diluted its worthless.

 

[BankDude]

Thought about this too... You coulda got a bad batch of gas...

 

[smarrs12]

I thought about it being bad gas.. but filled up 5 different places since then, and problem is just gettin worse

 

[Bass_Waves]

No cel? Maybe u got a biased o2 sensor or a bad maf. Like test your o2 sensor and see if its ok. When your burning that much fuel, most of it ends up in your tail pipe but goes thru your o2 sensor. Liquid can damage it. As for bad maf. Your air/fuel mixture can be wrong and dump more fuel than necessary. Give it a shot. Maybe that can be or not.

I sent this thru the Intranet™

 

[smarrs12]

How do you "test" 02 censor? I thought if its bad, the check engine light would come on? Whats cel?

 

[white balt]

CEL = check engine light.

what signature?

 

[smarrs12]

Whats a signature?

 

[Bass_Waves]

Whats a signature?

There's a way to do a pin point test on the sensor. Not sure how nut there is a way. Not all the time ot will throw a code. Like I said it may be biased. May give the ecm 1 reading but it could be measuring bad so it could cause more fuel to be burned.

White balt signature. Like mines on bottom


I sent this thru the Intranet™

 

[white balt]

Lol, people have been confused by it lately lmao.

what signature?

 

[Bass_Waves]

Lol, people have been confused by it lately lmao.

what signature?

I would imagine ppl may still not know what tapatalk is

I sent this thru the Intranet™

 

[GMCustomerService]

Have you had any luck with your Cobalt since your original post, smarrs12? Hope things have improved!
Sarah (Assisting Vanessa)
GM Customer Service

 

[smarrs12]

No they haven't.. seems to be getting worse.
Going in tomorrow and getting a trans flush, new fuel filter, and tire rotation. Hopefully that helps...

 

[ivaylonikolov]

As a full time mechanic i know No auto maker recommends using engine/trans conditioners at all .If u wanna have a long lasting good running engine do not wait till oil life is low .Ive serviced many gas/diesel engines and the ones that had the oil done on time or earlier didnt have any gunk/sludge inside .I change the oil in my cars every 3000-4000 miles tops with synthetic oil -at coast 30 bucks i dont think u can go wrong ,plus i have never seen engine ever damaged by changing oil too early , changing late ..... thants another story