Hi!

I'm getting Godawful gas mileage on my car (in the sig below)...12.8 MPG. Is there anything I can do to improve performance? Here's what I've done to keep gas mileage up:

K&N
92 Octane gasoline
Oil change about 4-5000 miles ago
Cats replaced
Muffler replaced

Any ideas?

Thanks!

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1989 Trans Am GTA: 350 TPI, N10 Dual Exhaust

Mods: K&N, Dynomax Super Turbo muffler, 3.5" intermediate pipe, twin Dynomax Super converters, Dunlop Sport 4000 tires.

 

Sounds like one of your sensors has gone and the car is probably running rich. A bad CTS or O2 sensor can contribute to bad mileage. You need to throw it on a scanner and see whats up. I ran a tank of gas out in a 120 mile trip due to bad fuel injectors.

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Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

What kind of scanner do you suggest? I found a device that analyzes engine codes (or something like that) when you plug it into the engine, and it's compatible with my car. Or should I take it to a shop and have them analyze it, and ask them for a printout when it's done?

Thanks!



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1989 Trans Am GTA: 350 TPI, N10 Dual Exhaust

Mods: K&N, Dynomax Super Turbo muffler, 3.5" intermediate pipe, twin Dynomax Super converters, Dunlop Sport 4000 tires.

 

First, but basic -- If you're running a 700R4, make sure that you haven't lost overdrive -- mine had some problems shifting into overdrive a while back and gas mileage will drop off severely.

However, have you noticed any other symptoms? i.e. difficult hot starts, rough idling, power loss, etc.

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1985 Trans Am - rough and ready
1976 Corvette Stingray - not so rough, but always ready

 

Go to your local Napa or Autozone or whatever and get a bottle of GB 44K Fuel System Treatment, its $25 but it is well worth it. I ran a bottle through my 84 Z28 and I gained 40 miles per tank! Then, when I bought my 87 IROC, I ran a full bottle through and gained 30 miles per tank!

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End with 2.77:1 Gears.

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

Soon to Come: 7.625" 10 Bolt with 3.42s and Accel TPI Intake Base