So it's been over a month since this has happened, fortunately I work from home AND have another car to drive which is one of the reasons why I haven't done anything yet....

So the Service Engine Soon light came on back on Jan 15 while I was sitting idling at Sears Automotive to get a new battery. I had them check the codes and he told me it was bank 1 and bank 2 running lean.

I'm freaking out because running lean on a boosted G is NEVER a good thing and I still have to drive home. So I'm taking it very easy on the throttle on the way home although the driveability did not seem any different. When I'm about 2 miles from the house the SES light goes out but I decide to stop by AutoZone right by my house to see if the codes still show up.

AutoZone confirmed that P0171 and P0174 codes were still being thrown which indicate Fuel System Lean, Bank 1 & Bank 2.

The possible causes for these codes according to the AutoZone printout are:
1. Low fuel pressure or restricted flow
2. Ignition system fault
3. Large vacuum leak
4. Faulty MAF sensor

Along with these codes being thrown, my gas mileage has gone down the sheetter which leads me to believe a few possible things. The next time I started up the engine the SES light was back on again.

So finally this past weekend I got the car up on jack stands and pulled the engine cover off and inspected all the fuel lines for any suspicious cracking or weathering and didn't see anything. I started the engine (SES light on immediately) and looked around at all the fuel lines for any leaks (with the Vortech there is a lot of additional fuel lines) and I did not see any leaks whatsoever. This rules out the low mpg's as a fuel leak.

I haven't changed anything since this started happening so I'm not entirely sure what could have caused this to happen. I hadn't driven the car for probably a month because I had been out of town for 3 weeks during the holidays. When I came back the battery was dead so I charged it overnight and it seemed fine the next day. I drove it down the street, parked it for a few hours and then it started fine and drove back home. Then I didn't drive it again for 5 days and it was nearly dead again which is when I decided to just go get a new battery from Sears.

My plan for now is to go clean the MAF sensor and see if that helps any. Through some searching on these codes, I did find a few threads that pointed to the O2 sensors being bad, just seems strange that they would both go out at the same time. This could very well explain why I'm burning so much gas if the O2 sensors are mis-reading and causing the fuel injectors to actually dump a ton more fuel since it's reading a lean condition.

The last thing I have in mind is to use /SeaFoamsales#p/u to clean everything out from the intake to the injectors to the lifters. I'm hoping that if the spark plugs are carboned up from excess fuel or the O2 sensors are carboned up, that this Seafoam stuff will help clean everything out. It's an inexpensive way to clean out a bunch of the carbon buildup so I figured it couldn't hurt

So in the end if anyone has any ideas or similar experiences, please help a brother out!

 

R1 posted some feedback in another thread as well:

my reply:

 

Not sure if this is any help but i had this same code about a month and a half ago and my intake was loose, did a fuel injection cleaning, and picked up some maf cleaner. Did the work, reset the code and no more....

 

Yea Jon, check all your vaccum lines. Usually you will hear a hissing. If a vaccum leak is present the engine is sucking more air than normal and will be lean. Also like you said check the plugs. If its time to replace now is a good time. Hopefully it will be a simple fix. Another thought would be to replace the fuel filter but the g does not have a servicable one. Wish you were close so i could inspect and drive your car some more. lol. I still has your oem decklid, bumper and skirts

 

^+1 I agree with R1 BTW running lean= less fuel just some info thats all.

 

Thanks JaE35, hopefully I will have the same results after cleaning the MAF sensor and checking the intake!

I will definitely check all the vacuum lines although like I said nothing had changed when the problem started other than throwing the battery charger on ... but who knows maybe I bumped a line somewhere. It's kinda hard to hear a vacuum leak on my car when the blower is spinning and then spitting out air through the bypass valve

I thought about the fuel filter as well which is in the gas tank. With the Vortech setup there is a fuel management unit and an auxiliary fuel pump that sits under the engine compartment which is one of the reasons I was considering the seafoam to potentially clear up any buildup that might be in there.

As for my old parts, sorry man I didn't mean for you to be my personal storage warehouse! Will have to get that stuff picked up from you soon, either that or get it sold so you can install it for someone else!

I've kinda been wondering if you could do anything about the fitment of my Strafe sides...

 

lol, thanks for that insight

Yes the sensor is detecting a lean condition and is therefore trying to compensate by dumping MOAR fuel which equals my 10 mpg That mainly tells me that a sensor is malfunctioning somewhere or being thrown off due to a vacuum leak or something similar.

 

haha wow steven. does this sound familiar at all? I had a lot of similar fuel issues. my problem was that I needed a fuel return system. do you have one? I dont think that's your problem, but MAF is the first thing i would clean.

 

Yeah I actually thought about your scenario with the return fuel as I had never really looked into them before. Although it doesn't make sense to me that I could run the boosted setup I have for the last 40,000 miles of daily driving, track, and autocross and now all of a sudden I would need a return fuel system?

I'm hoping it comes down to either the MAF sensor or maybe the pre-cat O2 sensors. Before I get to the O2 sensor point I think I'm going to try the seafoam cleaner first to clean out any gunk!

 

id say replace spark plugs, o2 sensors, fuel pump, MAF in that order. one of those should fix it

 

What up mr. BeerViper!!! Love how you've hit all threads with this link... awesome.

Anyways, sounds like you've got good sound advice to work from. I agree completely with Rob and the others. Start with the simple stuff and then get into the complex. Hopefully the simple will resolve your situation. Also don't forget that when these cars have a check engine light, the go into stupid mode and dump fuel like crazy anyway.

 

Yea I miss read what you said, d**n four hours of sleep!

 

I agree with the others. I would clean the MAF, replace the spark plugs, and check for vac leaks first. That's all easy cheap stuff to do. If there are still issues I would start looking at the O2 sensors, fuel and ignition systems. I really think if one of the O2 sensors were out, you would get a code specifically related to this.

 

Also jon check the fuses for the o2 sensors

 

I don't think that your plugs being bad would cause your MPG to go down so bad. At what it would take for your plugs to be that bad, the car probably wouldn't run very good at all. Not a bad idea to change them anyway though, since you are boosted. That would give you peace of mind that you don't have any melted plugs, and they're cheap enough.

You could have a vac leak. An old trick to check is to get a straw, put one end near your ear, and use the other end to check different areas under the hood. If you come across a good leak, you will hear it hiss pretty good when you get close to it. Another way is to start moving vacuum lines. When you move the hose that's leaking, the idle should pick up,

I think that you're probably looking at a o2 sensor issue, or possibly MAF sensor. If you were actually running lean enough to throw a code, and hit any boost at all, you would notice the pinging for sure. I would try to borrow a known good MAF sensor first, and reset the codes. See if that works. If you can rule out the MAF sensor, I would move on to looking at the o2 sensors. I'll look around and see if I can find the way to actually test both the MAF and o2 sensors for our cars. Don't just throw parts at it, that's expensive and only works when you throw the right one.