Well I had good gas mileage
#1
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Location: Windsor, California
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Car: 1986 Iroc-Z, 1980 Cadillac Eldorado
Engine: Iroc- 5.0, Caddy-5.7
Transmission: 700R4
Axle/Gears: 3.23
Well I had good gas mileage
Well after I installed the headers I was able to get 17 when driving kinda hard, 18 to 19 when driving normally, and 20+ when driving it easliy. For some reason I'm getting like 13 to 14. If anyone remembers, I had another post fairly recently talking about how my car was stalling and how I was having some weird charging system problems. Now, the charging seems to be fine, but my gas mileage gets worse and worse every time. The spark plug wires must have 3 or 4 k miles max on them, the cap and rotor may have 13k or 14, and the plugs may have 3 to 4k on them as well. This just kinda came on. My throttle is sticking (always has) so I'll be installing another throttle body, readjusting the iac, and the tps (I just adjusted the tps and set it at .50-.51 or so).
Does anyone have any ideas?
Oh yeah it's a 1986 Iroc-Z 305 tpi
Does anyone have any ideas?
Oh yeah it's a 1986 Iroc-Z 305 tpi
Last edited by tpi305; 11-12-2009 at 02:56 AM.
#2
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Car: 1986 Iroc-Z, 1980 Cadillac Eldorado
Engine: Iroc- 5.0, Caddy-5.7
Transmission: 700R4
Axle/Gears: 3.23
Re: Well I had good gas mileage
Oh yeah and I also just replaced my air filters and I cleaned the maf, but that didn't help. The o2 sensor has no more than 7-10k miles on it. It runs just as good as it always has and there are no codes. The ses light isn't on.
Last edited by tpi305; 11-12-2009 at 03:26 AM.
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Car: 1986 Iroc-Z, 1980 Cadillac Eldorado
Engine: Iroc- 5.0, Caddy-5.7
Transmission: 700R4
Axle/Gears: 3.23
Re: Well I had good gas mileage
This is gonna be a hard one isn't it
#4
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Re: Well I had good gas mileage
Could have something to do along with losing back pressure possibly on the exhaust system.
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Car: 87 GTA / G8 GT
Engine: 5.7L / 6.0L
Transmission: auto's :(
Re: Well I had good gas mileage
This might sound dumb but it just happened to me..is your fuel tank leaking?
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Car: 1986 Iroc-Z, 1980 Cadillac Eldorado
Engine: Iroc- 5.0, Caddy-5.7
Transmission: 700R4
Axle/Gears: 3.23
Re: Well I had good gas mileage
It's funny because I'm not noticing a lack in power at all, but my gas mileage sucks. The only thing I've done is put on 18" wheels (reproduction chrome irocs; my old rims were cracked), BUT they are the same size in diameter...well, within like 3/16 of an inch. I used some online program to check the change in the speedometer reading with these tires and it said that when my speedometer says 65, I'm really doing 65.18 .
Edit: Wait....that couldn't be it right? If that was the problem, wouldn't it be saying I went much farther than I really did, rather than say I didn't go as far as I really did?
Last edited by tpi305; 11-13-2009 at 12:45 AM.
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