Some good news
Thread Starter
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Posts like a 4 Banger
Joined: Feb 2008
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From: St.Louis area

22mpg is HORRIBLE for the hwy. You should be getting 28 minumum.
I saw this statement in another thread about a Buick Park Ave...
http://www.bonnevilleclub.com/forum/...033117#1033117
I am now going to change the spark plug wires and the plugs to the recommendations given.
I am willing to make the necesary mods over the next few months to get this car in a better mpg range as I learn more.
Napa has this to clean the intake and injectors. The treatment is $100.
http://www.motorvac.com/products/CarbonCleanMCS245.html
To do or not to do?
You'd be better off getting a FLOWMATCHED set from FIE than buying that.
No mods. Or maybe you mis-spoke. Until you achieve 28mpg highway at 65mph, you shouldn't even be considering modding.
No mods. Or maybe you mis-spoke. Until you achieve 28mpg highway at 65mph, you shouldn't even be considering modding.
Thread Starter
Senior Member
Posts like a 4 Banger
Joined: Feb 2008
Posts: 101
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From: St.Louis area

Ohhh!!!
28 mpg at 65mph!
I drive Chicago alot, and I know that driving above the speed limit is frowned upon, so I left out the part that I was speeding. IL State Police are pretty predictable as to where the do radar and there are a lot of them. 22 this last trip! I call I-55 the "Gauntlet" because of all the radar traps.
I averaged 85 the whole way there and got 360 miles on a fresh tank. When I refilled I put in 16gallons. That comes to 22.5 mpg. I believe if I had set the cruise and did 65 it would of been higher. Sorry for the confusion.
I will be posting in some more threads in performance/brainstorming with more questions soon.
28 mpg at 65mph!
I drive Chicago alot, and I know that driving above the speed limit is frowned upon, so I left out the part that I was speeding. IL State Police are pretty predictable as to where the do radar and there are a lot of them. 22 this last trip! I call I-55 the "Gauntlet" because of all the radar traps.
I averaged 85 the whole way there and got 360 miles on a fresh tank. When I refilled I put in 16gallons. That comes to 22.5 mpg. I believe if I had set the cruise and did 65 it would of been higher. Sorry for the confusion.
I will be posting in some more threads in performance/brainstorming with more questions soon.
Thread Starter
Senior Member
Posts like a 4 Banger
Joined: Feb 2008
Posts: 101
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From: St.Louis area

Ha! Good news went to bad news!LOL
Appreciate the heads up and am very happy to know that even better gas milage is attainable.
I am doing the Cat redo with the Magnaflow Cat.(2 weeks from now) I am going to leave the rest of the exhaust stock for now and work on new plugs and wires. How hard are the back plugs to get to for DIY?
After the tune-up, I will have new PCV, new fuel filter(pressure at 41psi), new air filter, new plugs and wires. Is there anything else with the tune-up that I am missing?
Should I do the Injector cleaner service for $100?
The only thing else I have done is adjusted the BCS.
Car runs great and am so excited that it can run better! This car gets better each day!
Appreciate the heads up and am very happy to know that even better gas milage is attainable.
I am doing the Cat redo with the Magnaflow Cat.(2 weeks from now) I am going to leave the rest of the exhaust stock for now and work on new plugs and wires. How hard are the back plugs to get to for DIY?
After the tune-up, I will have new PCV, new fuel filter(pressure at 41psi), new air filter, new plugs and wires. Is there anything else with the tune-up that I am missing?
Should I do the Injector cleaner service for $100?
The only thing else I have done is adjusted the BCS.
Car runs great and am so excited that it can run better! This car gets better each day!
The rear plugs can be a challenge, but very doable. I found that by removing the strut tower brace I could get at the plugs much easier. Slide the shield away from the plug, wear a pair of leather or good mechanics gloves, grab the plug boot and twist and pull. You may damage a plug wire, so be prepared to have to replace them. When you install the plugs, be sure to put some di-electric grease in the boot first.
When you are finished, make certain that no plug wire is touching the wire to the O2 sensor.
When you are finished, make certain that no plug wire is touching the wire to the O2 sensor.
Thread Starter
Senior Member
Posts like a 4 Banger
Joined: Feb 2008
Posts: 101
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From: St.Louis area

Hans, do O2 sensors wear out like spark plugs or other such items?
I will change it out though.
I am getting a EGR code that comes off and on. Check engine light does not stay lit.
The EGR is a recent replacement. I believe the car has been used more and driven harder so I may be blowing carbon out of the intake system. I have been using fuel injector cleaner also. May be related.
The tune up should help, the O2 sensor sounds like it will also. The EGR is up front and easy to remove and check.
I will change it out though.
I am getting a EGR code that comes off and on. Check engine light does not stay lit.
The EGR is a recent replacement. I believe the car has been used more and driven harder so I may be blowing carbon out of the intake system. I have been using fuel injector cleaner also. May be related.
The tune up should help, the O2 sensor sounds like it will also. The EGR is up front and easy to remove and check.


