M A F, poor gas mileage

My fuel mileage went from a high of 27 mpg when Buick was new in 2005 ,to 20 mpg. Been o n a constant decline. Stopped at local garage, picked his brain. He suggested claening M A F sensor. This morning I removed it, only two discover someone had cracked air plentum, tried to repair it. Also discovered the new air filter wasn't installed properly. Going to town to buy cleaner, hope this improves mpg.I glued cracks.

Looks like J.B. Weld?? good stuff.. I used it to repair my sons F150 pickup fan shroud.. 4 years and countin..

Had a Buick with a Series II 3800 V6 engine that did the same thing where the mileage dropped like you cited. If I recall, it needed to have a part replaced, which I think might have been the fuel pressure regulator. The MAF, or Mass Airflow Sensor, is something that may just need to be cleaned up some.

The glue you see is what I used to repair it. Someone had used something different. I'm hoping the cracks and improperly installed air filter is the cause for poor mileage. This is the first time I've even seen air filter.

Bought mag and throttle body cleaner.

Going to hire plugs and wires installed tomorrow.

Hope this brings back mileage.

Plugs in our SUV are specified in owner manual to be standard type plugs,like old copper core, not the newer 100,000 mile plugs. Had them changed couple months ago, mileage went up 2-4 mpg, depending on type of driving.

I have a 2004 Pontiac with a 3.4 L V-6, 185,000 miles. Its mileage went from 32 to 24 gradually. Nobody could give me a reason why. No codes, no noticeable loss in performance. I decided to have a look for myself. I found the vacuum line on the fuel pressure regulator swelled up from fuel. The fuel pressure regulator was leaking internally, allowing unmetered fuel to by-pass the throttle body. Put a real GM part on if that is what you need. I have not had good experience with aftermarket fuel pressure regulators.

Going to have new plugs and wires installed tomorrow. The OEM plugs are a special plug, the center part looks like a needle that comes to a point. Local garage had a name for them. Not copper core old style plugs.

I'm hoping to bring mpg back to when it was new. It 12 years old and only have 72.5k miles on it.

It runs great, doesn't use a drop of oil, just poor mileage.

Planning to keep the car for another 12 years if not longer.

Probably said Iridium plugs.

Ihatw when that happens ...

I hate when that happens ...

When you clean the butterfly spray the cleaner on your rag then wipe it off, NOT on the unit, might damage the seals/electronics.

John I think you are right. Iridium. That even sounds expensive. What should plugs and wires and installed cost?

wildcat,
I have a 2005 Buick Rendezvous with 3.4L. Because it pushes more air out of the way, EPA specs mine at 27 mpg best. When it was new at 75 mph on interstate, I would get 26.5 best. Staying under 65 mph on major roads, not interstate, I could get 27 with no AC.

My mpg has been dropping for a long time. Yesterday it got to 20 mpg on interstate and I decided enough is enough.

The throttle plate was dirty. I couldn't tell if the MAF was dirty, but I gave it a few shots of MAF cleaner.

I'm hoping to bring back my mpg.
geo

I dread those set ups its a dang fight and noting never lines up :evil:

http://www.aa1car.com/library/what_is_fuel_trim.htm

http://www.aa1car.com/library/poor_fuel_economy.htm

http://www.aa1car.com/library/maf_sensors.htm

They are only new the day you drive it off the lot its all down hill from there. I will say those are about as a free rolling car as I have ever driven. I had folks complain in the 90's when they got there act together on torque converter lock up they don't slow down when you let up on the throttle. That's one reason they get good fuel mileage on a long trip they are very efficient in lock up.

One of my jokes with a customer that told me to drive his mid 90's olds/buick (don't remember but one are the other) for a few weeks any were I wanted to go. I drove it on a 200 mile trip one way when he showed up he asked how did it do did I find out why it would not slow down when you let off the throttle . I told him once I got on I95 I ran it up to 75 let off the throttle and it coasted for the next 150 miles I did not see a problem.

Don't recall exact amount, since I had other work done on the car at the same time, but it seems like parts were like 90 bucks at the dealer for my wifes 06 3.8. That was wires and plugs.

I may be able to offer a few things...
First, changing plugs and wires is not likely to help you much. If they are Iridium plugs, they are rated for over 100,000 miles. Unless you are getting misfire or rough running, the plugs should be fine. Also, how will you feel after you spend a pant load of money on plugs and wires and is doesn't help?
Next, I would seriously look at things like the Oxygen sensor, MAF sensor and fuel pressure regulator.

GM vehicles use the Oxygen sensor as a feedback device for trimming the mixture. A sensor out of calibration will have a big effect on fuel consumption. Also note that GM's oxygen sensors are a weak point in their systems.

Mass Air flow sensor is another major controller of mixture. Cleaning it may help. This is one sensor that can go bad WITHOUT SETTING A CODE!!! There is no secondary reference to verify if it is out of range or out of calibration. It doesn't take a lot to have a major effect on fuel mileage.

Fuel pressure regulator. If this one is starting to leak, it will also cause a drop in mileage. Keep in mind that unless this is a "flex fuel" vehicle, the ethanol on the gas WILL attack the rubber in the diaphragm in the regulator. Regardless of what the Midwestern corn farmers tell you about it not causing problems.

You would be well advised to do (or hire done) some diagnostics BEFORE you start throwing parts at it.

You can take that style MAF apart to clean. That is the only way to get it really clean. Be careful of the sensing elements, though, they are very fine wires.

(quoted from post at 09:01:30 02/03/17) You can take that style MAF apart to clean. That is the only way to get it really clean. Be careful of the sensing elements, though, they are very fine wires.

Click to expand...

Nutter one of my favorite Quoits before I touch a MAF sensor wire.

I need you blessing cuzz by me touching it, it may fudge it up, What I mean by you blessing it is to bless it with your wallet.

Its hard to splain to those that have not been there but those that have can tell if a cleaning will do the trick. I have never broke a wire that has been blessed