I've been trying to improve my gas mileage. On my last two full tanks, I had 12 mpg and 11 mpg. I did not go wide open throttle on either of those tanks, and I drove at normal speeds. It did not just start either. It's been crappy ever since I dropped in the 355. My mods are in the sig. I know I shouldn't expect great gas mileage, but everyone else is getting much better. Any suggestions on what to do? Fuel pressure is around 46-48 PSI. The O2 sensor is not reading rich either. ANY help would be greatly appreciated. Thanks.

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1984 Camaro Sport Coupe - Rebuilt 355 S/D TPI L98, Crane 2032 CompuCam, Crane adjustable fuel pressure regulator, MSD Blaster coil, custom burned PROM, stock TPI intake, Accel 24# injectors, gutted air box with K&N filters
F41 Suspension Package, 700R4 Tranny, TCI Breakaway torque converter, 3.27 Posi Rear
Hooker Shorty Headers, Catco High-Flow 3" Cat, Flowmaster 3" American Thunder Cat-Back
JVC Head Unit, Kenwood Amp, Pioneer 4x6's and Pioneer 6x9's

Best 1/4 Mile Run:
13.847 @ 95.91 MPH

1992 1LE B4C Police Camaro RS - 305 TPI 5-Speed

 

What type of driving do you do? Is it mostly city? Stop and go? Or do you actually get some cruise time in there?

I found that driving around the small town where I live, I get between 17-20 mpg, but, if I drive around in, say, cleveland, mileage drops to around 12.

My car is a basically stock 88 formula 350, with a few of the bolt on mods, and an MSD ignition box.

 

you wouldn't happen to be running a 160*° Thermostat? I hear that it might not let the car go into Closed loop, which is where your car should be the most efficient..

I could be wrong, but it makes sence...

John

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G O D BLESS AMERICA

http://www.3rdgenformula.com
87 Formula 5.1 TPI Auto Modified (Yellow/Black)

87 Formula TPI (5 Speed) Yellow/Gray STOCK

14.8sec 1967 Buick Riviera
1990 Buick Riviera (driver)
83 Camaro
83 T/A

 

I do not get very good mileage driving all city either, but I do get on it quite a bit.
Just check and see that it is getting into closed loop. hope this helps

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14.48@93.72mph 2.03 60 ft
After Pulley's 14.31@95.18, 2.14 60 ft

 

I am running a stock thermostat (195 I believe) and it is going into closed loop. I checked with my dad's scanner. Thanks for the replies. Any other ideas?

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1984 Camaro Sport Coupe - Rebuilt 355 S/D TPI L98, Crane 2032 CompuCam, Crane adjustable fuel pressure regulator, MSD Blaster coil, custom burned PROM, stock TPI intake, Accel 24# injectors, gutted air box with K&N filters
F41 Suspension Package, 700R4 Tranny, TCI Breakaway torque converter, 3.27 Posi Rear
Hooker Shorty Headers, Catco High-Flow 3" Cat, Flowmaster 3" American Thunder Cat-Back
JVC Head Unit, Kenwood Amp, Pioneer 4x6's and Pioneer 6x9's

Best 1/4 Mile Run:
13.847 @ 95.91 MPH

1992 1LE B4C Police Camaro RS - 305 TPI 5-Speed

 

what are:
park idle: MAP kPa/v, tps v, O2 v, block learn/fuel integrator
park drive: MAP kPa/v, tps v, O2 v, block learn/fuel integrator
2000rpm cruise: MAP kPa/v, tps v, O2 v, block learn/fuel integrator
3000rpm cruise: MAP kPa/v, tps v, O2 v, block learn/fuel integrator
4000rpm cruise: MAP kPa/v, tps v, O2 v, block learn/fuel integrator
the 3000 and 4000rpm redings can be in second gear
as local law authorities frown on high-speed
neighborhood passes.
a passenger taking readings while testing would
be best.
why so much fuel pressure?
your custom chip was before or after the new engine
and add-ons??
airdeano


[This message has been edited by airdeano (edited December 05, 2001).]

 

Might want to look at the misc. stuff like tire alignment, tire pressure, replace the wheel bearings or at least clean out the old grease.